| You are correct with the wiring, to confirm I added a simple wiring diagram to show that.
A typical heating circuit will be a 20 amp with #12-2 cable with ground, starting at a 20 amp two pole circuit breaker, feed the thermostat and then onto the heater(s) to be controlled by that stat.
A 20 amp 240 volt heating circuit can handle up to a maximum of 3840 watts of heat. so you can use one heater at 3840 watts, or any multiple amount of heaters that add up to no more that 3840 watts.
One circuit can feed more than one thermostat, each that only controls one room. So for example, if there are three rooms, each having a 1000 watt heater, totals 3000 watts, these can all fit on one circuit, just need to feed the circuit to three stats, each controlling it's one heater.
There is no difference in solid or stranded wire. Most cable, Romex, BX, and MC, is typically all solid. Stranded wire is typically used for conduit systems, as solid wire, while still used, is much more difficult to pull than stranded wire. | 
Linear Mode
