Given the size of most disc drives for a very long time now, and yours may be an exception, I do not tend to worry myself about the disc footprint (how much space a given application itself takes up) of virtually any program.
My personal favorite for a strict PDF reader (as opposed to reader/editor) is Tracker Software's PDF-XChange Viewer and I've posted the link to the download page for same on the other thread I've given the link to previously.
Brian AKA Bri the Tech Guy (my website address is in my profile) Windows 10 Home, 64-bit, Version 1709, Build 16299
Here is a test to find out whether your mission in life is complete. If you’re alive, it isn’t.
~ Lauren Bacall