So it looks like my three options are a two post, four post, and small/portable unit - all have their pros/cons.
4 post is nice because I have more confidence storing a car up top, but bad because it is harder to do work, especially suspension/wheel stuff.
2 post scares me in a residential unit because the concrete thickness is is at the lower range of what they recommend.
Portible units are nice for small jobs, but obviously no storing of other cars.
I think I have decided on a 2 post, but am curious about an idea.
Has anyone made steel plate base extenders that would widen the footprint? I think this would give me peace of mind on the 2 post and tilt the scale for me choosing that. Does anyone see flaws in this idea?