I had a Super Stick 60 for several years. I had 3 different engines on it. I always balanced it on the main spar. That would be a good starting place. Never had any problem with the CG. I didn't give it much thought. The plane balanced by moving the battery around in the radio compartment. I started out with a well used Super Tiger 61. Then had a ASP 65 four stroke for a short while/ But must of its use was with a Saito 91. It flew good with all the engines. I just used a 4 channel radio with it.