It'd be better to have a sprung, pivoting bar or pad on either side of the throttle lever, running the length of its travel,so one can extend a finger to tap one or both brakes without any concern about throttle position. It'd be tempting to put buttons on the throttle handle for brakes, but that could lead to some serious "whoopsies".

I think the monowheel Europas use a single brake lever on the throttle handle, sort of like working a motorcycle hand brake, and steering is courtesy of rudder/tailwheel input. Bet that's pretty easy to learn to use.