As I recall Solace has a tutorial on their site to answer your questions. Running SS props, just bought a 4 blade Solace to replace a 3 blade because I wanted better control at cruising speeds and wasn't worried about top end...Crestliner 1750 and 115 Merc. I was running a Mercury Laser II 3 blade, 20P and top end was hitting the rev limiter at 5250 RPMS with the speed at 47-48 running about 5% slip.
Replaced with the Solace 4 blade 19P and the top end dropped to 44-45 and RPMs right at 5000 but biting better at about 4% slip....4th blade helped there. I was really surprised that the Solace performed that well considering less pitch and another paddle in the water to turn water. The props are different manufacturers and different designs due to their different functions...so any similarity in performance is pure chance.
As tutorials tell you, 4 blade shape is designed to get the stern up, usually on heavy stern loaded boats or regular boats that cruise just above planing speeds, or big water where you want good control of the boat at slower speeds battling wind and waves. 3 blade shape is for top end and bow lift. They are designed for high speed (within the equipment limitations) and to get that you have to reduce hull contact with the water (drag). They usually have a lot of "rake" and good "cupping" to get the bow up and out of the water, running near the surface (high trim angle) and improving top end.
