I supported my 1956 cab with a 4x4 wood post through the door opening and chained it to the roof truss close to the ceiling. I added a piece of rope at the front and rear just to keep it hanging level in the event it got accidently bumped. It hung that way for 14 years with no ill effects.
Your way would work fine as long as you chained the open ends of the support brackets up to the ceiling joist before dropping the cab down.
Mike B
