Ok, so I've been playing with a few props since my 525SC rebuild. HP is now around 600.

Tried a stock Maximus 24 (that's a big prop). Excellent planning, & did real well in rough water, but not much on the top end. I could only get 4700 rpm, 59mph.
I came across an OSO'r selling a labbed Maximus 24, the tube was shortned, & the diameter was reduced to about 14.7, & cup was added.
He was kind enough to allow me to give it a try before commiting to buy.
Ran it yesterday...
5300 rpm 73 mph (GPS)...planning was excellent, & the added cup was a huge help with trim. I was able to trim this out. I did however, seem to lose some mid-range. At 4000 rpm, I was 52 mph. With the labbed bravo 28, same rpm, I was 56, but it fell on it's face at W.O.T...
Sooo...Is it the reduced diameter that is giving me good top end numbers, and causing the reduced mid-range? Obviously, I can't have diameter added, but I could just start from scratch on a new 24 Maximus, & not have the diameter reduced so much. I do like the rest of the recipe of this prop...thus, my dilimea.
I do feel as though there is still a good 300 - 400 quality rpms in the engine, but I don't think I pursue going there. It sounded awesome at 5300, & it spun it quite easily.

It's the reduced pitch that is causing your loss of midrange. Many boaters have 2 sets of props for this very reason. Think of the high pitch prop as overdrive on a car.

IMHO I would contact B Blades. He will most likely recommend a 4 blade Revolution 4 26P to start. You can try them all using his loaner program, and when you find one closest to what you need he can tweak it from there. Either way he will share his knowledge over the phone without commitment on your part, that alone is worth the call.