Need to determine prop size and use of through hub exhaust

[H2oallyear]

Looking to select the proper stainless prop. 3 or 4 blade for my 1980 johnson 150 on the back of a 16.5 ft Larson Spitefire 5000. Basically a banshee Deltacraft XLT Glastron CXX style boat. Running at 2500 feet. Good all round performance is what I am after. It came with a 17 aluminum. Runs 6100 rpm wot and a 19 aluminum running at about 5600 rpm wot. I got about 45 mph on the gps with the 19 but had 3 people in the boat. Also, I have an old hardly used 21 pitch steel prop off my 1983 Merc 175 that fits except there is no through hub exhaust on this prop so the exhaust would go around the hub and mix with the blades. Would this cause excessive cavitation?

 

[steelespike]

I believe there is a specialty prop that lets exhaust flow over it rather than through it.
If it worked on the 175 Merc I would think it would work on the Johnson.
Probably good for speed but pretty useless for water sports or heavy boats.