Crank length and hill climbs

The top speed is whatever setup Chuck Edwall is riding. It’s much more about the rider than the crank length.

Klaas’ idea of Total Gear Ratio will give you an idea of how much speedup you can expect with a given setup, based on how fast you are with a different setup:

The level of control is a personal thing as well. It’s safe to say that there’s not much control on a 36 with cranks shorter than 125mm; descending and turning can be smoother, but any sort of situation where you have to fight your momentum is a losing battle.