i have a GP 60 Cub and i have a problem taking off if i slowly apply throttle. the cub will either make a hard sharp right or left turn without warning. i toed in the gear and it helped a bit. But i have found a way that works for me. When im lined up down the runway and im ready to go, I just apply full power all at once. The Cub pulls straight, I stear with the rudder . pull back on the elevator and im airborne. Im running a saito .91 and its got tons of power.
I think part of the problem for cubs is that the main gear are placed far forward and are very close together.