Hay guys.
I'm kind of building a model, which is partialy my own design. It's an improvment (or so I hope) of a plane I falt spinned into the ground[:-]. It had a problem with rolling out of knife edge back to level flight so I thought I should increase the wing dihedral. Unfortunatly not enough of the wing survived to find out what was the dihedral. So the question is how do I determin the right dihedral, while gluing the wings together only once?
Are there any rules that should get me close?

It's a low wing patternish 40 sized plane with a moderate sweep in the wing.

Thanks to all and any help

If it rolled back to level from knife-edge, you need to reduce dihedral. It rolls because of dihedral.

There's lots of material written about this in the past. Try some keyword searches on "roll coupling", "knife edge dihedra" and any others you can think of. Lots of material with solutions and suggestions will come out of it.