The .91FX is ringed, correct? A ringed engines first runs aren't quite as critical as to ambient temp. (IMO )

Is it going in your air boat?

If so, I would just cruise around for the first tank at a rather rich setting, then lean it out to a slightly rich 2 cycling mode for the 2nd tank, and after a few more tanks that way, you should be good to wail on it [8D]