Yes...with todays modern formulations a ratio of half of the OEM specs is acceptable. I've been running half ratio on an old Evinrude "Big Twin" on an old fishing boat for years...no problems. I also run my 73 Panther at 40:1.
"Well, boys, we got three engines out, we got more holes in us than a horse trader's mule, the radio is gone and we're leaking fuel and if we was flying any lower why we'd need sleigh bells on this thing"
'96 Arctic Cat ZRT 600
'94 Arctic Cat Cougar
'73 Arctic Cat Panther
Member of Lodge #27 F&AM