VWalton,
For break-in definately use a smaller dia. and higher pitch prop. My TT91 wouldn't run well at all with a 14X6 until I ran a bunch of fuel through it on the test stand with a 12X8 (maybe an 11X somethin'). I ran it incredibly rich at almost WOT. Slowly leaned it over the next few tanks and started working on the low end. Still a bit tight but runs great now with a 13X8. I believe my HSN is around 5 1/4 turns out.
Before I did a thorough break-in it spat more props, threw more propnuts and trashed more spinners than any engine I ever saw! (It didn't like the tank position with it's inverted instalation).
With over 1.5 gal of fuel through it the compression is showing no signs of letting up. It is almost too much (cold)!
Do a lengthy, really rich break-in for the TT 91 and you'll be happier. Yeah, the choke assembly works wonders for this engine.
Keep an eye on the valve clearances for the first few weeks of flying. At least till it runs really reliably through the throttle range.

Good Luck
Jeff