I find that anything with two bolts (3T Dorico, Doric, for example) can be levelled precisely to where you want it.
The carbon ones are very easy to crush, however.
My question- and probably one for AndyP: I need to do a race-test this weekend, I'll be down in Winchester so no turbo, so where can I go to try to hold 300 watts for an hour and a half?
Turbo trainer?