I know the manual says 0.021"-0.024", but the spark plugs that the manual also says to buy come with a gap of like 0.030"...I'm kinda in the same situation and don't really know what to do with the new spark plugs...
Gap the plugs to spec.Don't leave them as they come out of the box.They are mostly wrong.
With the fuel,you can run the super unleaded 98 oct. without any problem.
Lead used to be added to fuel as an upper cylinder lubricant for 4 stroke motors.2 stroke motors have oil added to the fuel.Problem solved.Hope this helps