Gerhard has some 24/10 and 24/12 4 blade props that Biela made custom for me when I was flying the SPT-10. I believe he has one or so of each left as well as 24/14 3 blade props.
Also, if he only has standard props, those will be fine. The standard prop is rated to 8,000 RPM and the Turbo 10,000 RPM. You probably will not be close to 8,000 RPM inflight so you will be fine.
Beave