Yes, the Meraki MS425 supports flexible stacking, and once you configure the stacking ports via the Meraki Dashboard, those settings persist on the switches even before the physical stack cables are connected and the MS425 does not have dedicated stack ports. Instead, any port can be configured as a stack port.
Switch Stacks - Cisco Meraki Documentation
I am not a Cisco Meraki employee. My suggestions are based on documentation of Meraki best practices and day-to-day experience.
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