When I roast or bake chicken legs (about 10) I roast them for about 2 hours on 350 wet so they never dry out. I am cooking today nearly 100 legs in 3 full size pans (32 legs each pan) for a buffet table. How much longer will I need to roast them so the meat pulls back from the bone and they are tender. I will still roast them "wet" and covered. I also have access to commercial convection ovens.
Id suggest turning the heat down to 300 and giving them around 3 to 3 and half hours. Keeping it low means if the buffet is late which is often the case they won't dry out left in the oven.