In the current APA engineered wood guide they indicate floor sheathing is recommended to have 1/8" space at all edges and tongue and groove. How is this achieved?
I've seen contractors use pennys.... They just drop a penney in between panels. It gives them a bit of a gap while they nail everything together. Then when they're done nailing they pick of the pennies and place them along the next panel line.
The clips also provide a means to keep the panels aligned vertically in unblocked edge situations. This helps with the appearance of roofing materials.