Welcome to the forum Pinker, also be sure to come and see us all at the SPAD World forum.
well for a start YOU are correct, if he's balanced it behind the spar (did you say 4 INCHES!!!) he's lucky to land it at all, paraphrsing from some thing i saw: nose heavy is bad

, tail heavy is sad :cry: .
the CG should be about 25% - 30% of mean average cord including ailerons.
the CG info for all the SPAD planes is on the build instructions, stick with these and you wont be far wrong.
good luck and have fun
PS if he balanced the CAP the same i'm not surprised it is matchsticks