The sparky told me that a lot of the bathroom units are wired so that you can only have either the light or the heat on, not both, and that you should always have the exhaust fan on when the heat lamp is on. Mine wasn't wired that way, so 5 minutes later I had these 3 rules created;
I then added a humidity sensor located between the shower and the fan, and added the Smart Humidity Fan app from @napalmcsr which automatically turns the fan on/off.
Then, in webCoRE I created 2 rules to control the heat lamp in certain conditions;
and
Edit: I used webCoRE, as a non-programmer I find it easier to use sometimes, and had some complex rules set up on it from SmartThings that I wasn't easily able to convert to Rule Machine. I needed to use it for those rules, so figured I would use it here too, even though they are quite simple.