ORIGINAL: jerzdvt
I like the larger size because I plan on using 6 channels with 6 servos in the future, for flaps and ailerons, etc.
That would probably be more like 7 servos on 5 channels, 1 throttle, 1 rudder, 1elevator, 2 ailerons, 2 flaps.

Up to an OS 55AX would be ok on most 40 size planes.
I am not a big fan of Super Tiger and after my limited experienxe with a g90 I will never own another one, but that is me, you will get mixed reviews on them.
Good luck with yours.