Dave, I didn't say it was a hanno, I just said that the hanno's were swinging big props.

I'd be aiming for a 12x8 on an RF, and possibly a bit bigger on an RF-P. That's making the assumption that some pinhead hasn't cut the header down to 5" to make it rev it's box off. If that's the case, then all bets are off.

Oh and I hear you on the 20% oil, my 61SF looks pretty nasty inside these days.