Assemble the plane and get ity ready to fly. Fuel tank empty.
Put your fingers under the wing on the leading spare of the wing.
The plane should be slightly nose heavy.Thats good.
If tail heavy thats bad,adjust to slightly nose heavy.
What we have here is t-l-a-r. (that looks about right).
Have an experience flier take it up and trim it out.
He should be able to tell if you need to move weight around
in the plane to make it handle better.