It depends on a few things. On an electric helicopter, most speed controls want to see a flat throttle curve on all banks. On glow and gas helicopters, it depends on the governor that you are planning to use. For instance, I use Aerospire MultiGov Pro governors on my fuel helicopters.
The Aerospire governors want to see a linear throttle curve on normal bank, and V curves on IU 1 and 2 banks. But the integral governors in most FBL units want to see a flat throttle curve for normal bank. and IU 1 and 2.