Biscuits: I've changed the original biscuit recipe and started using this one from Melissa and while I like the parmesan and scallions in the biscuits, don't go out of your way to add them. The biscuits are good without them (of course).
Filling amount: These biscuits keep well so if you only want to make one or two sandwiches, reduce the filling accordingly (I usually make all the greens and just eat the extras for lunch).