Can you tell us the shape of both the Stab TE and the elevator LE.  The original Nobler was round on both and used cloth hinges which roll the elevator around the radius of the stab.  If you used the DuBro type you would normally leave the TE of the stab square and either round or angle the elevator to allow deflection.  If it is angled and the same thickness, it will always be higher/lower than the stab.  If you have not covered the elevators yet you can increase the angle till it is even with the stab which will be significant at 45 degrees or better, round it slightly at the rear of the angle.  BUT....

IMHO this is not much of an issue with the stab and I probably would leave it as is unless it was "bothering" me because I doubt it will have much effect on performance.  If you need 45 degrees deflection you are already well outside the performance envelope.  If you need full deflection I doubt that the turbulence at the hinge line will be significantly different once they are sealed.  Many of us make our elevators about 1/8" thinner than the stab but that is for a different reason.   I use Robarts hinges on the stab and imbed the elevator 1/4" into the stab.  On flaps I use the flat wing TE with rounded flap LE.

Stab LE/TE shape has been a frequent topic here.  If you can trick the search into finding some of the threads you will need popcorn to read it all.

Good Luck - Ken

It just struck me that all of the Noblers that I remember, up to and including the Bear, had rounded Stab TE's.  What plans are you working from?  As to your proposed solution.  Works for me.

Ken

I guess that explains it.  I thought I had seen all of the original and all of the Gieseke variants that Bob and his friends flew and I don't recall ever seeing one with a flat Stab TE.  Guess I was wrong, I missed that one.  Does it also have the flat stab and round LE or is it airfoiled?

Ken