Well, if the glow plug' threads are ruined, you could close off the hole and try the engine on model diesel fuel.

It might surprise you.

My Enya .60 four-stroke runs on diesel, without any modifications. To be fair the CR is a tad low and a Cetane additive helps with reliability. The CR on your OS might be higher than 8:1 ... which is the CR on my Enya.

Anyway, you don't have much to lose by giving it a try.