RE: SPRING STARTERS?
I'm a newbee with gasoline engines but I've been running large (Moki 180 and OS FX 1.60) 2-stroke glows for the past few years. Even a Sullivan Dynatron running from a 24volt power source can have difficulty turning over these engines when they are new, especially the Moki. The OS is never a problem because a quick backflip of the prop against compression is usually enough.
In anycase, my GP Christen Eagle II has a Fuji BT-50SA on the nose. I've been told this engine is sometimes difficult to start so I opted for the spring starter. Another reason for the spring starter vs the heavy-duty spin starter is the aluminum spinner provided with this airplane could not hold up to a spin starter (it usess a 2-piece A frame connected to the backplate with ribets to mound the spinner face, instead of a bolt attached to the prop shaft). You would literally rip the spinner off the nose with a dynatron or a megatron. The little extra weight from the spring starter did not cause a major concern with my application -- what's 8 ounces to an 18 1/2 pound airplane.