bassmanh
When using flaperons you still have aileron control tho it may be less depending on your radio. The flaperon mix will droop your ailerons to act as flaps but still allow one to raise and the other to drop more.

You probably will not need this feature on a T-6 but I don't know which T-6 kit you are referring to. The best thing to do is learn the characteristics of the plane without the flaperons and then try them out at a safe altitude to see their effect.

As for coupling the rudder and ailerons, personally I would suggest learning how to use the rudder. Again I don't know which T-6 you have so I don't know its flight characteristics. If it has big barn-door ailerons coupling might help.