Hi,
Due to covid, I know that sea foam worked for me well for 18 months. It did not work at 24 months. That was in my generator with a full tank of premium fuel.
The generator would not keep running under a light load. I added a treatment intended for de icing and it ran fine--if a bit smelly.
I had previous used stabile but it left the generator running rough and hard to start after 8 months.
My gas tank is 55 us gallons--I use two cans of sea foam. The last two gas fills of the season are premium fuel.