Wm, this was a free flight design, right? And you're going to use RC? If so, you can reduce the downthrust and compensate with elevator trim. The old free flight designs had to have a floating glide and also be stable under power without swooping up into a loop. The wing typically had more incidence than the stab, which gave longitudinal stability, but if you trim it to glide well, it will swoop up under power, hence the downthrust. Downthrust works by directing prop wash under the stab, which lowers the nose. With downthrust, you can have high or low power without trim change. Nice for RC, but essential for free flight.

Lots of people reduce the incidence of the wing, but that actually reduces the effective downthrust (just visualize the flying surfaces and engine without the fuselage), so don't change it.

What you will need to do is carry some down elevator when you fly. If you haven't built it yet, you can increase the stab incidence so it is closer to the incidence of the wing. That, of course, is like down elevator. In either case, the prop wash will strike the stab/elevator underneath which is what downthrust does. If you reduced the wing incidence, you wouldn't have to carry down trim under power, but you would have to add more up elevator in the glide mode. It works, but you lose the helpful effect of the downthrust, so you have more work to do with elevator trim while flying.

I'm afraid I'm making this sound more complicated than it really is - a couple of diagrams would make it easier. Does this make sense? Bottom line...being able to control the elevator makes the downthrust much less critical. There is no reason to change the wing incidence.

Jim