We are managing global campaigns by using the options like compare contact fields, wait step & email scheduling in campaign canvas.
By doing nested compare contact fields we are distributing the contacts from segment based on their country field.After that, for first time in wait step we are using wait until specific date & time to choose time zones. For second stage emails on wards, we are placing no.of days to wait ( no need to bother about counting only business days). We can restrict that in email scheduling option by selecting the Days of the week ,start time, end time & we can choose time zone.