For doing 3D you want a low pitch prop. Probably the best for the 91 is an APC 16x4W, but if that is too big, you'll have to drop down to something in the 15" range.

Now, the higher the pitch, the more speed you'll get, but at a cost of losing power to pull out of a hover with.

It's a trade off. 3D planes are not meant to fly fast and fast planes are not meant to do 3D

In either case, I would go with the APC over a MAS