Afms are the way to go with gaskets. Most of us run them. If you use 93 pump, use ethanol treatment.  It will prevent gumming of the carb and jets and i believe it may help with possible oil seperation at lower temps.  I could be wrong on that, but i run ethanol treatment in all my carb'd engines.. From lawnmower to yfz 450.  Got tired of cleaning corn film out of all my carbs.
927 is excellent oil.  Getting squish cut can be done by any builder on here.  When squish is done and head and cylinder are PROPERLY decked, you should have no problems blowing head gaskets on a 250.