simple answer is the best you can afford! i always run mine off the high octane pump fuel (bp ultimate) and then add some TTS (i want to get some MOTUL soon..)
and get the fuel when you need it. it will spoil if you leave it too long. especially the premix 2 stroke.
but in saying that i ran only premix 2 stroke in my old modded cag with the RD head kit in it and ran fine without problems for maybe 3 hours or run time total? i felt the only difference was how easy it started. nothing else aside from that really.
but as crash says dump some toluene into the fuel to bring up its octane rating
and if you get to 16:1 reach for the methanol
