If the raid fail, Zoro could have potentially have 2 weeks to heal as per Hawkins stating when Wano started '' a month from now ''.
Act 1 - 1 day
Interlude
Act 2 - 2 weeks time
interlude
Act 3 - 1 night(day)
interlude - 2 weeks time
Act 4 - 1 day(marines, blackbeard, war)
short interlude
Act 5 - 1 day conclusion(feast)