If you do radiant floor heat make sure you think ahead where a hoist will be placed. The tubes should be placed around where the uprights are placed and the crete under those should be deeper for better support. In floor radiant is great heat but better if you are using the shop continuously. If it's just a weekend hobby thing it does take a while to heat up and depending on your climate you need to run it at low temperature when you're not in there working. (just as you would with any conventional heat) The heat loss when opening doors is a bunch of bunk. The concrete slab is a huge heat sink and the temp recovers almost immediately. The better you insulate the more efficient the heat will be.
