One,
CG for S1 Ringmaster is 1 1/2" behind the leading edge as a starting point, closer to the leading edge is better then rearward. Like Ken said if it floats up when the engine quits it is tail heavy, (this is not normally the case as they tend to be nose heavy with most engine/mufflers), remove tail weight (if you have it) or add a heavier muffler, prop or spinner). Make sure you have your handle set for neutral properly, very small changes in this position can make flying more challenging. I like to set my handle for straight up and down with no bias. This gives you more wrist movement and less need for arm movement. Also, set the control horn length for slow movement by using the outer holes. On the S1 Ringmaster you only need about 20 degrees up and down, if it is going more move it down (away from the elevator) a hole at a time.
Leadouts are not real critical but with common 0.015" SS cable lines they are set about 1/2" behind the CG locations, so for the S1 since it is a straight leading edge the center of the leadouts would be 2 to 2 1/4" back from the leading edge at the tip.
Best, DennisT