Gear reduction a problem? Meh either that or you have a heavier head doing it.
I don't need no stinkin' spark arrestor. If I set a fire, I manage to notice it, because I have seen pictures of fires and hear descriptions, like an urban myth I am sure i could figure out a fire by tasting and touching it, (LOL as if I wouldn't notice).
Anyway, do the arrestor pull, or get a new muffler, and/or clean the exhaust port and expect the rest of the muffler to be aging. Your call.
It's a trade off, more oil mix ratio and you save the bearings but clog the exhaust more. I can live with that instead of the flywheel colliding with the coil.
These are the little things one deals with when something runs a long time, that there is oil carbon residue buildup. Any 2 cycle has a finite lifespan shorter than an equivalent quality 4 cycle, a case contrary to the norm of more complexity meaning more to break and probably sooner.