I have had several Ultra Sticks and at low throttle settings they will fly noticeably tail low. You give them full power and they are fine.

I have had a LT40 ARf for some 10 years and it didn't fly tail low when slow because it had about 8 degrees positive incidence in the wing. but at higher power settings the trim would change and the plane would climb. I made a shim to go under the rear of the wing to reduce the tendency to climb. Now it goes around tail low when flying slow. It is a great landing plane though