root, I tried both props when I had a .46FX in my Pizazz (A lot like the Twist). The rev-up was slower with the 12.25x3.75 if I remember right, but not much. The plane would come off the ground just a bit quicker with this prop. The .46FX would spin the 12x4 faster. I ended up swapping the .46 for a .50 with only a small gain in power. I think you will be happy with the way that .46FX/ 12x4 work together on the Twist.