Ron, I don't know if this helps/fits your situation however the #1 most space-efficient thing I did in my little shop was to line the walls with worksurfaces for the stationary bench machines (drill press, disk/belt sander, etc.), which lets me to roll the benches/floor machines underneath.
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I prefer tall-ish worksurfaces (40") so all my carts and floor machines are at a 37" height. The stationary worksurface are 2" thick, giving me ~1" of clearance underneath. Everything is on casters & I rotate benches/machines as needed to fit the project.
RMW