Biggest effect is on the runway and when you goose the throttle is when you could use it most.

I have flown with 0 thrust up to 3 deg. (3d only profile)

The skinny is that during high torque (nailing the throttle) with right thrust, less rudder correction. Use it if ya want , but don't think it's needed.


How do you mix for high alpha ? Get that Ice pick out
If you need a mix to fly high alpha 3d you may want to look into a better designed plane and stomp and burn whatever your flying.
Not too much I can't do as far as 3d goes, I've never needed a mix. Helped many learn 3d, never had to add a mix[X(]
Of course I've never tried to 3d a crappy design in order to help sales for some company giving me free planes, I guess mixes may be needed for that. IMHO