This is an age old problem,we all suffer from it.First of all your propane heater will be producing most of the condensation,if you could change it to electric or oil filled radiators things should improve,your breath causes a lot as well but you can't stop breathing,fit a Vent Axia or similar to draw the moisture out of the building or invest in a small de-humidifier.In the short term leave all doors and windows open for 30mins or so when you have finished working to allow the warm damp air to waft out.Insulate the roof first as this is where it drips down from when you leave(doesn't matter if it runs down the wall).
Woodworker
January 2010