I do it in the shop but need to clean up and cover everything before putting down the final topcoats to avoid dust and other particles. As far as surface, I use my old front-entrance door. It is a steel one and I mounted a really beefy lazy-susan bearing on it and put a piece of plywood on that. It provides a flat surface but allows me to rotate the work while spraying if I need to. I would really love to have a dedicated finishing area but it is just not in the cards for me.
Sometimes I think the surest sign that intelligent life exists elsewhere in the universe is that none of it has tried to contact us.
-Bill Watterson
Reminds me of my safari in Africa. Somebody forgot the corkscrew and for several days we had to live on nothing but food and water.
-W. C. Fields