Argento,
Is that 14x19p a Suzuki aluminum prop?
How high is your engine mounted?
Most seem to suggest a target rpm of 6200, which is the top of the Suzuki specified range for the DF140, as the engine gets the job done with revs instead of torque. My prop choice reflects my desire for best load carrying capacity and holeshot over maximum top speed.
I'm not knowlegable on DE hull weight and speed potential, but can share my story in hope it will help.
I've run the Whaler with the Suzuki aluminum 14x19p, and I go 42mph (68k) here on the lake, WOT 6500 rpm. I've also tried a 14x18p Stiletto Advantage stainless prop and hit the rev limiter at 41mph (66k) The Whaler weighs about 1600lbs bare boat, no engine, fuel or gear, and these tests were run at about 2700bs total. This season I will get a Stiletto Advantage 14x20p and expect my revs will drop to about 6300 WOT and maybe pickup 2km top speed. For your boat, that 18p Stiletto I had would probably be perfect, all else being equal.
A Stiletto Advantage is made by Precision Propeller in the USA, and is almost identical to the Suzuki Stainless props, but I'm unsure if the pitches compare directly. They can be found online for about $279 USD. If your 19p IS the aluminum one I'm suspecting, the 18p Stiletto should get you a few more revs and speed, plus the obvious durability. It will also make the engine feel a bit stronger, as the drive from my aluminum prop is less positive than the stainless one, probably due to less flex.
Engine height should be optimized to get maximum performance. Raising the engine one set of bolt holes could also get you 100-200 more revs out of the current prop. On my boat, my engine is mounted 1 set of bolts holes from the highest possible mounting position on the transom. I get no blow out in turns, but obviously would if I was mounted too high. An engine mounted too low will generate a lot of bow rise on holeshot, and will be slower and less efficient.
Again, I hope this is helpful. Cheers