Thanks for the inputs regarding PVC-tube in the wings!
We're done with the empennage now and both elevators are AFT heavy.
On the right one, we adjusted it per plans, but we had to bolt the removed leadpiece back onto the counterweight to get the elevator closer to neutral.
On the left one, we didn't do anything to the counterweight.
I guess we can solve the problem by adding lead in the forward part of the fiberglass tips before installing them.
Have anyone else encountered this?
The only reason I can think of is that we maybe put too much tanksealer in the aft part of the stiffners?? (But I don't think we overdid it....)