Why not fixed timing? This is not a 300 cid V-8, its a .65 cid 1 cylinder. The actual idle between fixed and variable timing was about 100 rpm with the timing set at 30 deg BDTC. A small adjustment on the carb and the idle was the same. In flight the cruse rpm was in the 14-1500 range. Kick back was less than when it was operated on glow.
In reality I have found that variable timing is of only a small use when the engine is less than 30cc (1.8 cid). On bigger engines the idle improvements make it worth while. But starting kick back is a null point. After all what is the difference between hand starting a G-62 on a magneto or if its on fixed timing. You just need to have your sh*t together when hand starting a big fixed timing engine, if your scared or timid it WILL bite you.