In the docs the recommended prop for the 120SP is a 20" x 12" 2 blade, 18" x 12" 3 blade or 15.5" x 12" 4 blade.

The vibration is the killer, I would be interested to hear how you go with the 120Sp, I had 3 die on me.

I also bought them for a twin and my TF Corsair.