Were I to decide to standardize on say 5% fuel for these, I could buy a jug of FAI, a jug of syn/cas 10%, blend them, then add castor to bring total oil up to 22%; 73/5/13.8cas/7.2syn would be fine IMHO. That's a very easy recipe to duplicate by visiting my LHS.
I wonder at what rpm these things start to come apart at stock..?
MJD