Caster is a great lubricant for air cooled motors. It takes alot of heat to burn it and therefore it stays around longer unburnt than the rest of the mixture. The down side is that with the right amount of heat it tends to gum up. This is bad for the working parts of a 4 stroke. Synthetic oil is being used more and more with better results as time goes on. We use synthetic oil in our gas motors after the breakin period with virtually no wear on the motor(it's that good!).
Synthetics actually hinder the breakin period because of their excellent lubrication properties. All the above is one of the reasons that YS's last so long. I can break down any of my 4 strokes and it will look virtually brand new inside!.
The fuel you have chosen is great for your motor. The one thing to remember though is AFTER THE FLYING DAY AND YOU DRAIN THE TANK, RUN YOUR YS UNTIL THERE IS NO LONGER ANY FUEL IN IT. CONTINUE TO CRANK IT WITH GLOW UNTIL IT WILL NO LONGER SPUTTER! This also ensures longivity. I've let motors sit for 6-9months like this, fueled them and flown. We will be happy to answer any other Q's you have to make your experience a trouble free one!