YAPQ- Yet Another Propping Question

[erebus]

I did some searching around and some testing and I have some results and some thoughts I'd like to throw out to the Seacraft Hive mind.

I have a 1975 18SF, which is pretty stock except for: fuel tank moved forward, batteries under the console, console itself moved forward about 6-8 inches.
Fuel tank is under deck 32 gallon.
Motor is 1998 Mercury 2 Stroke ELPTO 115 HP, 20 inch shaft (runs really good. Well maintained)
Motor is mounted 2nd hole from the top, but av plate was pretty much in line with the hull when I mounted it.
Prop is a Michigan Wheel 13.25x17 aluminum.

With me (230 lbs.) the wife (125 lbs.) full tank of gas (~200 lbs.) Plus some beach junk and enough food for a 230 pound guy, I feel like the motor is straining really, really hard to get the boat up on plane.
Almost feels like I'm dragging some dead weight.

Need to nail it up to almost 5000 RPM to get up on plane, takes about 5-10 seconds, levels off and cruises on plane happiest at about 19 kts at 4200 RPMs.
Yesterday it was nice an calm in Wellfleet Harbor so I did a full throttle test.
5400 RPMS and 27.4 kts (gps)
Looking over the stern, the AV plate on the motor is buried.
Shell fall off plane at 16 and below.

My thoughts are maybe the motor should be raised a hole or two?
Propping thoughts? I thought 13.25x17 would be just about perfect.
I have a stainless semi-cleaver style I was going to try thats 13x17. Maybe a little stern lifting will help?

Any thoughts, observations or opinions?

Thanks!