I recommend using this free tool to first determine how much heat you need.
<a href=”http://store.h-mac.com/heatersizing.html”>HEATER SIZING TOOLS</a>
Once you know how much heat you need, I recommend independent units for each space. This could save you money, as you are only heating the space you are working in. The Hot Dawg also comes in 2 stage. You could have 2 heaters, each with 2 stages, giving you 4 stages of heating total. Good luck.