How close to the start of maintenance/quarterly update can you safely publish a sandbox?

We are implementing all of our changes related to enabling Redwoods with 25C. This involves a lot of work within sandboxes (Autocomplete, Digital Assistant, Appearance, and Structure), which become unpublishable after the 25C maintenance and incredibly tedious and time-consuming to rebuild after. The main bucket is dozens of quick actions that we are disabling and creating some new ones, totaling roughly four hours of work to rebuild while the system is unavailable to end users.

How close to the start of a maintenance window can a sandbox be safely published so that we have time to build prior to maintenance? Is publishing fifteen minutes or an hour enough time to not be impacted by the maintenance?