All interesting stuff, if you go to any thing less than 40:1 thats your prorogative but outside the manufacturers recommendations, I note in the Evolutions users guide the state "synthetic oil intended for racing 2-stroke gasoline engines", in the MVVS guide they state "Mobil Racing 2T oil, or in bold letters "any quality bend-name synthetic oil intended for racing two stroke engines" now I don't know the quality of pennzoil or Amsoil 100-1, but would be interested if someone knows the quality of these compared to the Mobil Racing 2T oil?

Mike
EDIT: to add spec for Mobil 2T

Mobil 1 MX2T

Viscosity, ASTM D 445
cSt @ 40ºC 90
cSt @ 100ºC 13.8
Viscosity Index, ASTM D 2270 154
Sulfated Ash, wt%, ASTM D 874 0.15
Pour Point, ºC, ASTM D 97 -42
Flash Point, ºC, ASTM D 92 110
Density @15 ºC kg/l, ASTM D 4052 0.884