I would think as long as you keep one hive in the old location to collect the foragers, it wouldn't really mater what time you do it.
Put lots off bees & brood in the queenless box, & haul it to the new location. The queenright box will recover faster, than the other one.
Put lots off bees & brood in the queenless box, & haul it to the new location. The queenright box will recover faster, than the other one.