We use our ShipStation account for multiple dropship partners. Some of them require a specific label format.
Currently we have to stop fulfilment, change the label format, print labels for those particular dropship orders, then continue with the rest of the fulfilment.
It would be a nice feature to be able to select the label format for each store, either in the store settings, or by using automation rules.
We have the same situation, it should be customizable for each store (and each carrier) like the packing slips.