I have used Shell Gold for years as it has (had) no ethanl. Here is the great white north they recently added ethanol to it and I believe all gasolines , so, I am back to using regular pump gas and will continue to use stabil whn I put up the car for the winter.
In terms of unleaded (versus a leaded additive) I am fortunate to have an unleaded head on Ms. Triss but, over years of this conversation I really don't believe it makes a difference whether you use unleaded alone or unleaded plus an additive. The cost of an unleaded head and the cost of a conversion are about the same so, run it and if you need to repair it repair it but, in the meantime just have fun.