microwave/convection oven combo

If you'll Google the model number of the convection/microwave you have, you should find a manual that will tell you everything you want to know. There are much bigger questions than just which cookware. These are somewhat complicated units and manuals will have specifics about which settings cook what, etc. For more than just zapping something like a beverage, reading this manual is very important.

And... these microwave/convection ovens are not all the same so, unless you are getting advise from someone experienced with your specific model, the advice still won't do you much good.

Read the manual first and then go on from there, if need be.