An Eagle 2 is a great AC to learn on, and has no bad characteristics.

So I must ask, "What engine did you install?" If you already took out weight, it would seem that you have a bigger engine than the first owner.

The Eagle 2 works best with a 40-46 engine and a 10-6 prop.

Next, do you have the plans? If so find out where the CG is and check the balance.

As required; start moving things around to balance the AC. The first thing to move is the battery pack, slide it forward and back until it balances. If that is not enough - now you can start moving servos.

Stripping a plane is possible but a pain ... I try to avoid it.
BUT... if you must... get out your heat gun to soften the glue and peel the covering off. Lightly sand any hard to remove spots.

Good Luck!