lurker's comment: IIRC, 50/50 is what the game starts out with. I will either go at 100% if I'm going for a first tier tech(i.e. pottery), or 20%-30% if I'm shooting for a 2nd tier tech(writing). I think with the Iroquois, go at 100% for the wheel so you know where the horses are, then decide whats next. A swarm of Mounted Warriors early can really go after weak civ's nearby. Or, you could get on the Republic slingshot right away while doing an aggressive Rapid Early eXpansion phase. At Regent, you can afford some tech detours and still get the Republic Slingshot.