I think I'm just gonna have to try again. Aside from the little voids, the slightly wavy dimpled surface isn't great either. It does sand out, but it's not gonna be the perfectly flat surface like I started with on my plug. The little voids were only in a couple patches and obviously from trapped air. It was in areas where I first started trying to brush the coat on thin and it wasn't liking it, brush was dragging. might order the slower hardenener, maybe degass after mixing, and then not try putting a thin coat on. 
So anyway, I think I have some ideas on how to avoid the trapped air, but not sure what to do about the slightly wavy dimpled surface. I'm guessing this is from post curing off the tool so the surface coat got soft enough to start moving. Any suggestions on how to improve on this? Like I mentioned, I went no faster than 0.1 degree per minute, at times slower, and about a half hour soak every 10 degrees or so. Do I need to go even slower? Longer soaks? Maybe go up and back down a few times, starting at lower temps? Like maybe cure to 90c, back down to 20, then all the way up to 120? Or is it just gonna be really hard to avoid this surface distortion no matter what when curing off the plug? I'll also contact the manufacturer of the coat, see if they have recommendations. Open to suggestions though.

Just looked at the specs again for this surface coat. They recommend a post cure of 2 degrees per minute, which is like 20 times faster than what was recommended here, but I don't know if they are assumining you are curing on a tool. Maybe I went too slow?