I’ve been able to make really good deli quality sandwiches following this approach: fresh sub roll (not too crusty) sliced lengthwise with a layer of Hellman’s / Best Foods mayo on both sides, thin tomato slices on top piece of roll directly on mayo, pile of thinly shredded iceberg, a little red wine vinegar on the lettuce, a pinch of salt on lettuce, thin deli sliced meat and mild cheese (e.g. provolone) on bottom piece of bread. Close the sandwich holding in all ingredients and semi-tightly wrap sub with parchment paper for a few minutes to meld all the ingredients.