Hi Mike,
Your build is coming along nicely!
Regarding your propulsion plans; with 2700Kv on 4S you'll have close to 40.000 rpm unloaded, a 40 mm prop will be on the edge, as I can tell from experience, unless the pitch is lower than 1,4.
Also, as you'll no doubt know, your runs will be extremely short, as a plastic prop, even the Graupner K-series, will shed it's blades within feet as soon as the boat jumps a small wave when running full throttle...
I couldn't run anything bigger than a 31 mm metalprop on my 25" stepped hull with a 3660 2700Kv motor on 4S, I fried an ESC on the first testrun with a 40 mm Graupner prop, because I couldn't get beyond half throttle without flipping the boat... (violently).
As the boat had a floodchamber, I kept trying to get the boat to run full throttle, only to flip is again and again, until the ESC decided it had had enough.
As your boat doesn't seem to have a floodchamber (yet), you won't fry the ESC, as either, you'll have flipped the boat after a few feet, or the prop will be bladeless...
Regards, Jan.