When I make my sandwiches I go all out.
First a freshly toasted bun, most likely a wheat, with a little bit of mayo on the bun.
Followed by Turkey, and ham, both pan seared for a few minutes, to get them warm and juicy.
Then I take a slice of cheddar, a slice of provolone, and a slice of Mozzarella, rip them to pieces and place them in an oven safe container where I heat them up until they are more liquids than solids. I pour that cheese mixture over the sandwich to ensure a nice stringy cheese that covers the entire thing.
Then I take a thick slice of tomato and place it on top.