Bruce, you've got that backwards. The higher the second number the faster the speed will be, the lower the number, the better the vertical will be.

newb and Matt, with the 46AX and the tall landing gear, I would go with either a 12x4 or 11x5. I currently use an 11x5 on my SSE with a 46LA, and it's the best I can get with the engine I have. With the 46LA, you will much better performance. Also remember that you control the speed with the throttle, so find a prop that works best for the type of flying you want to do, and then just cut back the throttle when landing or just flying around.