I had a few conversations with a few people running glow to gas conversions. 16:1 ratio seems to be the optimal ratio. 8 ounces oil to 1 gallon gas or 5.9% oil.

The people I talked to have had no problems with there conversions running on the oil content over a year or more. The smallest engine was a Supertigre 51. I would guess the larger engine would need less oil since it passes more fuel per revolution.

All engines were ringed. I have a ST G90 converted to spark and a zama carb. I plan on running 16:1 with Pennzoil air cooled 2 cycle oil.

I hope this helps.