I too am learning to use a convection oven and not thrilled with it!
I have found that corning ware and pyrex products are well sized for the turntable. These are not made specifically for RVs but readily available and seem to work fine.
One thing I have learned the hard way is how long it takes to preheat the oven when you want to broil something. Mine takes something like 30 minutes to preheat and then it gets so hot that you need to be mindful of your heat alarm going off in the process.
Guess we are all a work in progress with these things and learning a new skill is supposed to ward off dementia so onward and upward with our convection ovens, eh?
Hope your Christmas dinner went well. You are brave to tackle that so soon!