Throttle motor speed

Hello

Does anybody know how fast I should be aiming for my throttles to be able to move? One tutorial has his 9RPM motor geared so that the handles take 7 seconds from idle to TOGA at maximum movement speed, but that seems a little slow to me!

There is no point in the handles being able to move much faster than they will ever need to in the sim, so can anyone give me a rough idea?

Thanks

kris