When I put two normal resistors in parallel I get half the resistance but twice the wattage. Does this apply to rheostats too? I would imagine because they are just large resistors are they not?
Yes, if you are just using the rheostat as a variable resistor.
You do have to be careful that you keep the settings the same so that the current flow divides equally between the two though.
If you are using them as voltage dividers, pulling current from the center tap it gets a little more complicated but the answer remains about the same.
