I believe they must start by hand. I start by hand all my glow engines (from Norvel 0.061 to OS BGX 3500) with the exception of 4-stroke (Saito 30). All engine start using chicken stick except that for Norvel whee use bare finger (6 inch prop), and for BGX where I use haevy padded leather glove (18 inch prop).

if engine doesn't start it must be: bad glow or not getting fuel or bad compression.

With magneto the starter is often a must because magneto needs to run fast through the coil (like at 1000 rpm) to give a good spark. Glow engine lights always regardless of speed - the speed is needed for compression. On old engines (or very new not broken yet) the compression will leak through ring so thet's why you need to flip it fast. But if piston-cylinder seal is fine, fuel goes into combustion and glow shines red then the engine must start by hand.

RysiuM