What propp size do you use on a 2006 Donzi 38ZR with 525 's ?
And what kind of speed should I expect?

Thanks
Hawkan

If the hull is similar to the 2008 and the drives the same ratios and heights, I can give you my experience.

I run Maximus 5 blade Mercury props. they are shortened and labbed more than the already shortened and labbed props you buy direct from Merc. I get 88MPH at 5100 RPM.