How long and what temp to cook crustless quiche for 200. Also covered or uncovered

There are a range of temperature and time recommendations (350 to 425F and 35 to 45 minutes), but recipes ALL recommend that top of quiche be slightly browned, and puffed up, with a testing knife coming out clean after it is dipped in the middle. If knife comes up with liquid, bake a few more minutes and test again.
Not clear to me how many quiches you are baking at one time.
Maybe do one as a test, to check how time and temp work in YOUR oven. Then do the rest, adjusting time and temp as needed depending on results of the test quiche.
And/or search/consult recipes for food service or "cooking for a crowd."
Good luck with your event/meal!