Matt, I think the OP may mean the Form's runtime, not a"Runtime" version of the database.

kb, if the user is only selecting parameters for record selection purposes then it is not necessary to change the Form's record Source, if however they are selecting the Fields to be shown on the form that is a lot more difficult, because you will have to change the Form's Structure to delete any fields that were originally on it, but not in the new Query.

So are you using the Query as a Record Filter?