To me, the size of the shop is determined by the things that one is going to
work on. If it is machining small parts, or making small things, small is
small. But, if it involves working on pieces of 20' long material, small
isn't good. You can put a lot of machinery in a small space, and do it in
an orderly efficient manner. But when you bring in the workpieces, that's
usually where the real space is needed.

I do tubular steel. If I want to make a 20' awning, the machinery to do
that will fit very easily in the back of a pickup with enough space left for
about four day laborers. But the space it takes to do this is larger unless
you want to work outside in the rain and wind.

YMMV.

Steve