Well...the engine guru at my field has 30 years in motors and machine shop experience and even used to teach how to build motors and do machining...his recommendation was to go with the ATF....his analogy to the old transmissions sitting for long times in junkyards with not a speck of rust is testament to how well this theory/practice works.

Maybe the mix of both Marvel air tool oil PLUS the ATF gives you the best of both worlds as Timbersnake suggests above...I always worry there would be some kind of weird chemical reaction or breakdown when mixing any lubricants or chemicals though but not sure if mixing these would have any negative effect???? I don't see why they would but I'm no chemist.