I go to my local airport with a few gas cans and get 100 octane low lead and blend it with premium unleaded. The 100 is also the best form of stabil going. I drain all the gas out of my antique snomobiles, lawn mover etc and put a gallon of that in and the next season, they start like they ran yesterday. As that fuel evaporates, it leaves no residue. Around here it is about a dollar a gallon more than premium. Also, you should be able to buy lead additive.
Oldsledz