30° BTDC is too much for the little 26cc engine, which runs best at 26 - 28°. Too early timing can destroy the connecting rod bearings and crankpin, as well as run hotter. Adding a head shim helps a lot here.
Adding two shims will cause a slight power loss of 100-200 rpm, but makes the engine run extremely sweet.
A plug gap of 0.020 should be about right with the RCexcl ignition. Normally, smaller gaps give erratic running.