I have the 46 LA, and I've flown a 10x6, 10x7, 11x4, 11x5, and 11X6. By far the best performance is with the 11x5. It turns it at 11,000 rpm. The 10x5 will probably increase your take off roll, since you won't get as much thrust. For comparison, I ran the numbers in Thrust HP. You should be getting about 10400 rpm from the 11x6 prop, for a thrust of about 4.7 lbs. The 11x5, at the same horsepower rating and 11,000 rpm, gives 5.3 lbs. The 10x5 should come in around 12500 rpm and 4.7 lbs. I also like the larger props for landing, since the larger disc gives better braking. Try the 11x5 APC with the 46 LA. I think you'll like it.

Brad