Are more complicated than I thought...
I thought bigger would be better, but MAN was I wrong!?!
One of the springs broke on the door, so I figured "what the hell, lets get the biggest ones I can find and install those..." Well, got done tensioning them, and when I went to open the door, all hell broke loose. Door FLEW open, and went straight into the opener. -_-
At that point, I figured I may have done something wrong, so I reset everything and tried again. Same result.
Was going to reset and try a third time, but decided to have a look online, and well, found there's more to it than just tossing some big ass springs on there. Found the approximate weight of the door, and have a better idea of what I actually need to order.
Lesson learned! Anyone else ever mess with tension springs on their garage door?