I went to F4s to obtain closer to the Reccomended WOT. The D5 was a bit to sluggish loaded. The F4s With half tank of fuel, 75 gal. 4 guests, gear, tabs up etc, I cruise at 3300-3400 rpm 26.5 mph. 4600 rpm is around 39-42 mph. I have not brought it up to WOT yet.
D5s were simular numbers, but it worked much harder to get on step and wanted tabs down a bit to ease the strain outta the hole.
DP Stainless is about double the price but feels smoother. I think just the pitch change gave me most of my gains for my purpose. The aluminum props perform well in DP configuation and dont give the damage up the spine if you whack an incidental object. Fuel burn has gone down noticably and she is in her happy spot at cruise.
Keep in mind the Osprey is around or over 8000 lbs loaded w gear.