you can use 1 thermostat to control multiple heating sourses as long as they are the SAME wattage and size (example: it is a fire hazard to use a 10gal size UTH and a piece of 1foot 4'' flexwatt on the same thermostat). IF you have the exact same type of heating sources on both (all) enclosures that are the same size its fine.
I recommend the Jonhson Controls or Ranco thermostats, you can get them from Rich at ReptileBaics.com (Rich has the BEST customer service in the industry, you can trust him completely). The Johnson and Ranco are about 80 prewired and ready to use out of the box. It may seem expensive..but honestly, its THE most important part in your husbandry system (yes, even more important than your snakes, because without a temp control device you could have an accident happen where your beloved pets are harmed or even killed). With a thermostat, you can set it and forget it. And the johnson/rancos are a medium price thermostat that is reliable and safe.