Dennis,
I do agree that you want to match the kV, but my only comment is that close enough is good enough. I've been obsessing a bit too much about my 880kV motor, thinking that if it were 800kV or 775kV that my battery would be happier. I am just a bit surprised that it doesn't seem to matter as much as I thought it would.
Now your 1500kV is pretty high, and maybe it would make a difference.
Another thing to think about is your plane. I chose the TF ARF Nobler because 1) I had one!, 2) they are pretty darn light (experience from my Brodak 40 powered one), and 3) they have a relatively thin airfoil compared to today's stunt behemoths! I was hoping the thinner airfoil would translate into a good cruising efficiency.
If you go to my old motor test thread
http://stunthanger.com/smf/index.php?topic=9256.0 , you can see that I tested (in the garage) the efficiency of my 3020-12 Stock motor (kV~1080) and my 3020-16 Hand wound motor (kV=880). The 880 kV was more efficient (~10%?) than the 1080 on a 4s pack at max power. Now this test does not account for the battery in the equation (I was only comparing how many average watts it took to run the ESC and motor at a fixed rpm with the same props. Taking the battery also into the equation should tilt the efficiency more towards the lower kV motor, but I haven't actually figured out how to do that--except by flying the plane. However you would need to fly in exactly the same weather to make a comparison (another way of saying that the differences are not gigantic). Maybe another way would be to run a test over a fixed period of time. Need to think about that one a bit.
By the way, the 775kV motor was just the 3014-16 mentioned in the above thread, but I re-terminated the windings from the original "Delta" configuration (which gave a kV=1250) to a "Wye" (or "Star") termination which gave a kV of 725. Too bad that was just a little too low a kV for the 4s battery. Because otherwise, it would have been a nice motor for the Nobler (and an ounce less weight than the 3020's!).