Currently I setup the local collection by mirroring the structure of the forms connected datasource. Once I have finished designing the form I change the datasource to the local collection and all the data seems to be persiting correctly.
However the validation does not seem to behave correctly. The required property of the datacard is set to true and yet on SubmitForm this is ignored.
I have resorted to using IsEmpty but if there is a better way I can toggle the is-required event of the datacard it would be much nicer.