AS long as no other watery vegetables are on board, I find that the moisture mostly evaporates in the oven. We do use a thick sauce so that may also help ameliorate the issue . . . water absorbed by sauce to balance out the whole deal. The only answer I have found fro a pizza with mushroom, onion, tomato, olives, bell pepper and spinach . . . is to par-cook the veggies before topping the pie. I haven’t gone that route for production yet. Though I may get there. Get a prep staff to load up a home type food dehydrator and dry the veggies out a little.