This is going back a bunch of years. I know your engine is a bit larger than ours was, but maybe this info is useful.
I found some notes and the props we used with our 69mm stroke x 90.5mm piston dia half-VW engine, tested to be 29hp using wood bar dyno. Mounted on a bit heavy LEU.
1st prop, Hegy, 54x22, max static was 3090rpm, was very sluggish on hi speed taxi tests, did not fly this one.
2nd prop, mfg unknown, 54x20, max static was 3160rpm, we flew this one. It was barely adequate for me, the heaviest guy around 220 lbs. It seemed to fly well with the lightest guy, about 150 lbs.
Some other notes I found from 2013 - don't know resulting performance of any of them:
- Sam Buchanan, 45 hp Casler, Tenn Prop, 58x24
- Scott Johnson, 78x92 engine, Tenn Prop, 54x24
- Alan ----, Mosler 78x92, ? mfg, 54x24
- Les Homan, Casler 94x86, Tenn prop, 58x24