My service was different, all 120 people and guests served at once so may not work for others with staggered serving times.
Baked potatoes, steamed, put onto a sheet pan, spritzed with oil and baked for 10-15 mins to crisp the skin.
When making a bechemel or similar I put milk/cream in a half pan in the steamer. When I was ready to make the sauce, whisked roux into it. Never a scorched bottom.
The ratio of custard mix for a hotel pan was always one gallon of whole milk...