RE: Cermark F-16 First Flight
8" back will be good for first flight, maybe a little nose heavy. Make sure you have some positive incidence when it is sitting on the ground or else it will be a bear to get to rotate for take off. My first flight it was nose heavy 8" CG and 0 positive incidence I ended up with full up elevator to get it to rotate and almost ran out of runway. Lengthend the nose gear about one inch and solved that problem. With the 91 in it instead of the 1.08 the balance point is about 9" back which seems to be perfect for my taste.
Hope this helps