From what I understand set-up with any of them is not that big of a deal, just takes a few hours, be patient and follow the directions.
Regarding your comment on scissor lifts somewhat interfering, on a Porsche with a mid or rear engine things aren't too bad, on a conventional car the framework can be a nuisance. I still use ramps to change the oil in the wife's and kids' cars since it's actually faster, if I had the individual lifts I referenced second center access would be much better.
Greg Smith Equipment likely has something you'd like, they were absolutely great to deal with.
My ceiling height is 9 foot and just barely enough to stack 2 porsches with the tops down on the atlas 8,000 pound lift. I measured very carefully before buying it to be sure they would fit since I needed to get 3 cars in a 2 car garage as well as work on them.
2004 boxster S 550 spyder
2008 porsche boxster S
2002 porsche carrera 4
Hybrid Mode
