So after 1 year's worth of trial and error, I think I finally found the optimum setup for our '05 192 with a 4.3l Volvo SX (1.79 ratio drive, WOT range of 4200 to 4600)......
Nauticus SmartTabs - SX9510-60 hole #3 (middle)
Precision Props Turbo 2+2TH, 14.25 x 22" 4-blade stainless steel.
With a full tank of fuel and just myself on onboard running into a fairly strong head wind with a 1' chop I was able to go 47 mph (on GPS) at 4500 RPM. Time to plane was under 3 seconds. No porpoising, no ventilation in tight turns and lateral stability was excellent.
With my wife and I in the boat and 3 kids in a 3-person tube, time to plane was 3 seconds, minimum planing speed was 16 mph. At 2900 rpm, we cruised/towed at 25 mph. No porpoising at all and the boat recovered very quickly after crossing other wakes.
For towing heavier water skiers, a 20" will be perfect although the WOT will exceed the max rating. I wouldn't run it at 4800 any way.
