Vree offers a computer course that increases your Science by 15%. In previous playthroughs, I wait until I get 101% at Normal from reading those Big Books of Science on Hard. This way, I end up with 116%. But is it really worth it to wait until you reach the maximum Science level from reading books, or should I take it sooner so I don't have to buy so many of those expensive books?

According to Per Jorner's 'The Nearly Ultimate Fallout Guide' you don't need more than 91.

You can find it here:
https://fallout.fandom.com/wiki/The_Nearly_Ultimate_Fallout_Guide
http://fallout.wikia.com/wiki/The_Nearly_Ultimate_Fallout_2_Guide

Both contain spoilers.