I used to use 11.5x4's on my .46's until yesterday.
Hooked up digital fish scale to plane and found the following for a TT .46, Tower Muffler, 10% fuel:
11.5x4 pulled high 6 lbs
12.25x3.75 pulled low-mid 7 lbs
12x4 pulled 8 lbs even (12,900)
12x4 spools same as 11.5x4 and it's my new prop for .46's
All props were APC
Ordered a 13x4 to try out.