What is the reasoning and effect of the Rickenbacker 12 string turned around method of stringing up the guitar with larger strings to the left of the lighter gauge strings on a right handed guitar?
Don't think it's any more than there's only the two ways to go, and Mr.(Herr?) Rickenbacker decided to go the other way. If anything, for strumming, it's slightly more effective, as the lowest note gets heard first, but that's minimal. For fingerpicking - unusual and not easy on 12-string - it maybe sounds better for the lower strings, which traditionally are thumb plucked, and obviously for the top E and B there's no difference anyway.