I don't have lab test results but I have run a lot of high rake, cupped props operated near the surface on non-professional, stock boats under 18' and 125 hp. If you go to the
www.go-fast.com site and dig around you will find a listing for a BAM prop slip calculator. That calculator involves the following items: gear ratio, engine rpm, prop pitch, how fast you would go if those numbers were applied to a "screw" in wood....no possible slip, how much slip is in your current setup, and how fast you can expect to go with the slip in the equation.
You can plug in numbers in all of these items except the one of which you are curious and hit the calculate button. You can work forward or backwards in the calculator depending on what you want to know.
You can also go to the top of this page and select Boat Parts and Accessories; scroll down to props; select the performance tutorial and read about all the prop parameters and how they affect the prop's performance.
I'll guarantee you, with first hand knowledge of running cupped props since the Ranger Bass Boat I bought new in 1989 that cupping improves prop "bite" which reduces slippage and reduced slippage results in MORE mph, not LESS, besides the fact that especially on boats that run out, say upwards of 35 mph, you get the effect of one extra inch of pitch........which if you think about it is just saying that it bites better than a non cupped prop! What this also does for you is that, if you are in the category where it can provide a notceable effect, it allows you to run a 1" lower pitched prop for the same top end but the effect of a lower pitch in the hole shot which will improve it and if pulling skiers, quicker pop-ups!
On a 14 ft john boat and 7 ? hp engine, I doubt it would do anything for you and I doubt they'd be available anyway.