Roasting large quantities of garlic: whole unpeeled heads or peeled cloves?
Garlic roasted as a head, as unpeeled cloves, or as peeled cloves is all much the same. It is just easier to handle unpeeled, and even easier when kept as a head

For easy results just trim the excess paper skin and roots of a whole garlic head, carefully trim just the tops of most of the cloves

Don't drizzle with oil and wrap in foil, this will just make a mess, and steam them more than roast them. Garlic is already very oily, it shouldn't need any more. Roasting items should be exposed to dry heat, not steam

Roast until soft and medium-dark brown. When cooled slightly, pull cloves apart and lay them out on a board. Squeeze out each clove using a firm spatula or other blunt tool. This should not be too messy. Wear disposable gloves if you don't like garlic on your hands