I knew someday, somebody would ask this.

My friend has a Stored in the ceiling layout.
1st problem - it cant be too big. Whats too big???
--- Small enough for you Yourself to raise & lower. You don't want to have to resort to getting someone to help you raise & lower it. Why?? - If you want to work on it until 1:00 Am "just to finish that project" you're stuck. Or how about - everyones out shopping - I just want to see .......(Insert any reason here)
--- Small enough that the plywood won't "bow from it's own weight" -- try to keep the track connected while the plywood it's nailed to, is bowing. - Stop it from bowing with more "benchwork"? - see "weight" above
--- Small enough that - Like my friend - you can hang it on 2 hooks yourself - and then swing it up by yourself. Would it bow????
--- The best idea so far is just build it in place - 6" higher than the hood of the car.
2nd Problem - Does my buddies O-27 platform work - Never did - every time we pulled it down off the ceiling, it took more (Way more) time to get it running than we had time to operate & enjoy it.
What did he do??? We re-built it on a Ping pong table (no you cant play ping-pong on it anymore). he got tired of trying to raise & lower the layout.