Delta CG
Rick, I would start with 20% of the main chord. (I have also heard suggestions of 11% of Mean Aerodynamic Chord, but I have not yet learned how to figurer the MAC)
Start with the CG forward. You may have to put more reflex (up) in the elevons to get it to fly, but it will fly. You can then slowly move the CG back slowly until the performance changes. As the CG moves back, you should need less reflex (which causes drag).
Put a pic up of your delta so we can see.