If you got the DPM Ultimate 40 from Cermark, DPM will not warranty the plane. Anyway I have the DPM Ultimate 40 and the slot for the horizontal stab was off on mine as well. It was about 1/2" from tip to tip. The wing was also out, and worse yet the other way. For the wing I added an 1/8” strip of balsa to 1 side of the wing saddle on the fuse which got the wing within 1/16” of begin square measued at the wing tips. For the tail I sanded and filled it appropriately until I got the tail close enough. The plane flies great. Even with an ARF you have be careful and ensure everything lines up correctly before the glue hits it. I’ve had the plane for over 2 years now and it has held up very well. I have not 1 problem to report on it.

I would suggest that even though DPM says the Saito .72 is too big that it is not too big an engine for this plane. Rather it is about perfect. There’s no way this plane would fly the way Dave says it will with a .46 2 stroke or a Saito .56. With a smaller engine it would have limited vertical I think. I don't think it would hover with my OS .46AX. Anyway that’s a personal choice.