Long time ago I had a similar problem and did a "running with scissors" restore. This means:
1.- Prepare normal configuration, test, etc for the new version.
2.- Prepare a restore configuration, with fsync=off, wallevel=minimal, whatever option gives you any speed advantage.
As the target was empty, if restore failed we could just clean and restart.
3.- Dump, boot with the restore configuration, restore, clean shutdown, switch to production configuration, boot again and follow on.
Time has passed and I lost my notes, but I remember the restore was much faster than doing it with the normal production configuration. Given current machine speeds, it maybe doable.
Francisco Olarte.
