Good questions, and I haven't quite checked into that. Actually, I'm still not fully aware how all the bonuses/penalties with tech research add up on deity... except I do know that (when teching normally), 15 beakers from your only city, will always end up putting slightly more beakers into the actual tech when you pay attention to it (haha). It's been a couple years since I remember reading the articles on how the tech pills are modified, I should look into it once again.
Also, when you do that fancy beaker-bank system (I don't know what else to call it, so I am just calling it Banking for now), sometimes you can have enough beakers to fill the cheapest tech open, but not fully have to commit to it... I think this depends on the last tech you toggled. But the weird thing is if you hit F6 you will see the cheapest tech colored Green. Anyhow, it can get a bit weird and strange sometimes, but I only use it in a few places in the game, so I don't know all the quirks yet. Obviously, it's silly to research fishing right away when you want to pop some huts in the next 5 turns. Noting worse then popping a tech when you are half-way or more completed it. Best to bank it... then pop the huts.. and then dump the beakers into a proper tech when not poping a hut.