RE: Small mods to an Balsa USA Enforcer...
I think you would be safe, but to be sure I'd put some lead in the nose to get the Cg 1/2' forward for the first flight.
The two, LEX and small canards, seem to be doing the same thing i.e. generating a vortex to increase lift at slow speed, I'd go with one or the other, my choice would me the LEX. If you are moving the canards I think they are so small that they would cause more problems than they are worth.