Just installed a 16GB set less than an hour ago myself, was very close to having to removing the GPU for room to release the lever, but all turned out good. 5 minute job.
I was a little queasy the first time installing RAM back in 2002/03 from 256MB to 2GB (a huge deal & upgrade at the time), but it went w/out a hitch. Have installed more sets than I can count since. The more one performs this task, the more it becomes easier.
One thing to always remember, and those who are experienced may forget (or take for granted) over time, is to be sure not to touch the gold plated pins, and be sure to touch a metal part of the case to prevent static discharge, which can damage any component connected to the motherboard. Also, do not perform this procedure on carpet, the chance of static buildup is much greater.
Lastly, if there is doubt, ask before performing if needed, there's always someone here who's seen most any situation & can advise. Like my install today, was very close to having to remove the GPU to complete the job. There are times when other components or wires needs to be removed for access, for first timers, take pictures of before removal/disconnection of anything, this has proven to be helpful several times for me.
Sometimes, it's not the ideal 5 minute job that we hope for.