Here are some numbers from my YS .53 FZ with no lowspeed needle, I have one with and one without.
Done today, about 55 degrees F

Fuel--WildCat Pro mix 20% nitro with 18% 95%/5% synthetic castor blend lube.
Hangar 9 SuperPlug Han 3011

Zinger 12x6-10----8,670 rpm it sounded terrible with this prop.

DynaThrust 12x6----10,560

Graupner 12X6--11.360-- this one was a surprise.

Master AirScrew 12x6 three blade---10,320 a pick up of about 400 rpm over the last time I tached it with this prop. about three more hours on it now.

All the 13x6s I have, have too large of holes in them and I have no suitable adapters.