The fuel you have will work fine. If you can get a little castor, well and good. If you can't don't worry about it.

Break the engine in a little rich of peak rpm. Run it for 5 minutes and shut it down for 30 minutes. Do this several time or about 12 to 14 ounces of fuel. Don't run the engine blubbering rich, this will ruin the taper fit of the piston to the cylinder. Don't go for peak rpm for the first couple of tanks. This will not let the machine work in the engine match up properly.

The engine is usually considered broken in when it will hold a steady idle and will advance throttle smoothly without stopping.