Update - received note from Peter Edhofer, (SEP Luftschrauben). SEP 23x14x4 Hamilton style designed for and is the most proven prop for the Moki S150 warbird. "No specific data for the UMS 150; should be similar".
https://www.sep-ls.com/23/11-14-Zoll...Hamilton-Style
I’ll give this a go and report back. Good news is the UMS-150 ignition supports RPM telemetry for detailed real-time and post flight analysis which has been helpful on my UMS-250.
Cheers