One more thing I see from your photo is the cg location
Now I know everyone is differnt on this issue.
But I like to set my planes CG on the AFT end of the range.
That mark, if that's your CG, is a little on the forward if not infront of the CG range, Moving the CG back a little will help it rotate as well,
Almost all kit designers set the CG on the main spar or visa versa, the mark in your photo looks like it's infont of the spar about 1/2" or so, I'd move the CG back to the spar (ckeck you instruction book to be sure) And I think you'll be happy with the way the plane becomes more responsive.

God luck