I am not sure the the YS engines.... In fact not sure with most any prop engine combo..... especially with speed!..
I would think that high pitch small prop is the way to go... but I have always looked on the forums about it,.
I would ask that q' in tht ys club forum.... Lots of guys in there with much experience with those geat engies.....
Stiil have not built mine.....
Also, I would go with 30 minepoxy on the stab, mixed with some filler/ milled fiberglass... guys have put stabs in with CA, but if you plan on goin fast, I would take the litle extra time and put in some good epoxy