RE: flap servo
Not really!. It would depend on the control horn set up and leverage. The Cougar has a huge set of flaps. The Derjet Cougar fuselage flaps have a vertical pushrod with a large leverage, so you could use them there.
Flaps should use Digital servos, you need holding power to resist the push back force and non digital servos on most flap set ups are too in consistant
Dw