Your opening post said what could you do to the prop to reduce torque roll, and also you wanted to use the mini stick to learn about propellers. I think you might not be going the easiest way to achieve your objectives.
As Bill has said everyone has had trouble with mini sticks rolling and I think the first model to overcome it was the K777 with a very high mounted wing and large tip plates. Coming now to the propeller aspect. The propeller torque formula says Torque= torque coefficient x air density x n squared x D to the fifth power. The torque coefficient is like the lift coefficient on a wing, as the wing depends on the wing section and wing area for lift so the prop depends on blade angle and blade area for thrust. Air density is pretty constant. Wing lift depends on flying speed squared, prop thrust depends on rotational speed n squared. There is also a certain analagy between the span of a wing and the diameter of a propeller in that a high aspect ratio of a wing and a large diameter on a propeller both lead to high efficiency. I am sorry but that is rather a long way round to say the propeller must be like that to absorb the torque in the motor because that is what flies the aeroplane. Now I have said all that I realize that Fred Rash has aready given an answer. Use a longer thinner motor taking more turns and then the propeller can be smaller.
I must say I enjoyed Don Lusarki's excellent analysis. Do you think Don that the high pitch propellers could also have stalled early in the flight giving the slow hover before the climb away d a stalled prop would absorb a lot of torque.