These are the, 'must have' requirements:
(1) A 1 1/2 inch (dress) gun belt. (1 3/4 inch gun belts are only for use with dungarees.)
(2) A gun belt that is 2 inches longer than you would normally wear. This will give you the option of carrying IWB/ITB.
(3) A gun belt with a 7 hole rather than a standard 5 hole tongue. (Same reason as above.)
If you go with one of the thinner, (dress) leather gun belts then you, definitely, want...