This is my first design and I have a couple of questions. The rocket is a BT-60 upper body and nose cone with 3 BT-20's at mid section and a section of BT-60 three inches long at the tail section. The three BT-20's are exposed between the upper and lower BT-60 sections. RocSim shows a marginal stability of 5.69 with three C6-7's loaded. Total rocket length is 38" long. Three fins on back with an individula fin span of 4" and they sweep back extending about 2" past the back of the rocket. Is my loaded stability good enough? With the engines unloaded the stability is 9.87. Is 3/32 balsa good enough for the fins or should I use 1/8" with a paper and glue coat? Any advice/tips would be appreciated.