I don't have a motor like that to compare Bill..... but looking at the structure, your resistance is not your impedance with this kind of motor. For an axial, it is good enough, but with tight airgaps, that will no longer be the case. You have in fact got synchronous impedance to worry about... not resistance.
...and the synchronous impedance will involve the resistance in the stator, and the frequency reactance of the stator at x rpm, and the amp turns in the stator trying to mess up the rotor field....
That makes a power graph very hard to guess at, unless you have a history with a certain type of motor, and thats called experience.
From the theoretical standpoint, it is just too hard to guess at the flux, ampturns,stauration..etc...... in short, it's all up in the air. I would not attempt to guess. It needs a simple bench test, and plot the figures. You may end up with a simple rule of thumb.... but I'm not that smart from here.
.........oztules