Should I first erase the LaCie using Disk Management erase tab or will partitioning it do that? I know to choose the "extended journal" option. I remember having to choose cluster[?] size when partitioning Windows, based on disk size, but I don't see that option currently on the Partition tab. With Windows I seem to remember the bootable partition had to be on the 1st partition of a drive. Is there anything I do during Partitioning to mark a volume bootable?
If you do want to start again, then I would Erase the drive first using the Erase tab. Then you can use the partition tab to setup the partitions you want. Having said that, if memory serves, if you just adjust the partitions without using the Erase first, I believe it will still nuke all the data on the partitions anyway (i.e. effectively erasing them anyway).
And yes, you will want to use "Mac OS Extended (Journaled)" as the format. And there is nothing you need to do with Disk Utility to make the partitions bootable. Technically any Mac OS partition (in "Mac world" terminology, a partition is typically referred to as a "volume", but more on that below) is capable of being bootable. To make a Mac volume bootable, it effectively just needs to have all the needed Mac OS system files on it to make it bootable (obviously a little different if you are talking about a Windows volume that is bootable using Bootcamp on an Intel Mac). And Disk Utility does not really do anything related to Mac OS system files. About the only thing in Disk Utility that you need to do to make sure the volume is bootable is to make sure it is using "GUID Partition Table" under the Partition Map Scheme in the information for the drive, but this should automatically be done when you format a drive/create partitions in Disk Utility on an Intel based Mac without you needing to do anything. And you don't need to worry about picking cluster size...that is done automatically for you.
If you don't want to start completely from scratch and keep the partitions you currently have, you should be able to do so as long as the amount of data that is on your computer that you want to backup/clone does not exceed the size of the volume/partition you want to clone/backup to. In this case, you said you have 300 GB and 200 GB partitions/volumes. If the amount of data you have on the Mac's internal hard drive is less than the 300 GB partition size, then you can just keep the partition sizes you have now. Of course, if you ever reach the point where your data reaches the point that it is more than 300 GB, then you would have to either get a new drive or adjust the sizes of the partitions at that point.
Just a quick note on drives/volumes/partitions on the Mac OS as it is a little different than for Windows. Generally the easiest way to think of it is the following: a drive is the physical device you put in the computer or attach externally to the computer; a partition is a sub-division of that physical device into smart "virtual" parts; and a volume is what the Mac OS calls a drive or partition within the OS. In terms of the last part, you can think of there being two "types" of volume...drives and partitions on a drive. In terms of the Mac OS, they behave and are essentially treated the same. When referring to a volume that is a "drive", it is essentially a "physical" drive that only has one partition...so the drive, partition, and volume are all the same thing. When referring to a volume that is a "partition", then that volume is a single partition that is one of more than one partitions on the physical drive...so a volume and partition are the same thing, but NOT the same as a drive (the only way you will "see" the drive when it has multiple partitions is when you open up Disk Utility...in the Finder and other aspects of the MacOS, you will only see the "partition" volumes, not the entire "drive"). Hope that makes sense.
Either way, once you have the drive setup how you want it, the SuperDuper! process should be rather straight forward. It should be something like this:
1) Select the drive you want to backup from the left pull down menu. If you have just the default naming that the Mac OS uses when being installed, then the internal drive is likely named "Macintosh HD". If you are using a different name for the internal drive/volume, then make sure you select whatever the name of that you used for the internal drive.
2) Select the drive/volume/partition you want to backup to from the right pull down menu. Do not select "Disk Image...". If it is a drive/volume/partition, it should have a drive capacity (in GB) next to the drive name. If you partition the external drive into multiple partitions (whether you keep what you have or do something new), then pick the partition name for the partition you want to clone/backup to. If you only have one partition for the external drive, then select the name for that single partition and it should have a capacity listed next to it close to about 500 GB (since it is a 500 GB drive).
3) For the third pull down menu below the first two pull down menus, select "Backup - all files". It should be the first item on the list.
4) Click the "Options..." button at the bottom of the SuperDuper! window. Click the box next to the "Repair permissions on <drive name>". Next, under the "During copy" pull down menu, select the "Erase <external drive/partition name>, then copy files from <internal drive name>" (where the parts in the <> brackets will be the actual name for the drives/partitions for your particular drives/partitions)...this should be the first option on the list. Next, under the "On successful completion" pull down menu, select "Do nothing" (should be first item on the list and likely already selected) unless you want to choose one of the other options (quit SuperDuper!, Shutdown computer, etc). You should not need to do anything on the "Advanced" tab. Then click the OK button.
5) If you have everything set correctly, then you can now click the "Copy Now" button. This will start the clone/backup process. It should ask you for your admin password and then confirm that you want to proceed. After you enter the password and confirm you want to proceed, the actual backup should start. You should get a window that lists various steps that will turn green when properly completed. It will take a while when you clone for the first time. One of those steps will be "Make bootable"...in other words, it should just be automatically done if you are copying all files including the Mac OS system files.
6) Assuming every thing runs fine, all the steps should turn green and say it is done. When that happens, you can quit SuperDuper!.
7) Try rebooting and booting to the external drive/partition that you backed up to.
For future backups/updates, you will use all the same settings (it should default to those setting when you have that external drive attached and you start up SuperDuper!...unless you setup and do a different backup setup using SuperDuper! after doing this backup...it always remembers the last backup settings you used) except for one. You will want to check the "During copy" setting after clicking the "Options..." button. For any updates, you will want that setting set to "Smart Update...". This will update (add new files, remove old files, etc) the backup rather than do it again from scratch each time (i.e. LOT faster than the first backup unless you add a TON of new files).
Is that clear enough? If not, let me know.