A 12 x anything will still require new gear so why not avoid the efficiency losses of a 3-blade and go with a gear that will clear the 13 x 6? If you must try the 3-bladed props, a MA 12 x 6 gives 9,700 RPM (richened from a peak of 9.900) on mine using Wildcat 15% at sea level. The 13 x 6 will hang that SE in a hover for as long as you can balance it at below 1/2 throttle and give you enough disk area to slow on a dime when you pull the throttle back.

quint