16 gauge wire souls be okay. You will need some spade terminal to crimp on the wire to connect to the t-stat...
Kevin,
Like Jared says - 2-conductor 16 ga stranded wire should be fine. The new thermostat comes with a pair of crimp-on spade connectors but you'll need the connectors for the wiring block end. My VMC44 uses a small ring connector, not sure what yours takes. If your machine has the same ring connectors, I'll throw a pair into the bag with your new thermostat, I have a bunch of them.
Jim