We have a mare that foaled standing up, with a normal delivery, which is an issue because she doesn't set off her Equipage alarm. You need to be there when your mare foals, so not having the alarm work is more of a problem for us, than the fact the mare is standing up. Mare stare might help, but just paying VERY close attention is your best bet. Our mare also foaled at noon this year, standing up, and never laid flat the year before so never set off the alarm. Mare Stare came through for us on that one!
Our stalls are 6X8 but we never use them that size for foaling. They have removable partitions so that the foaling stalls are at least 12 X 8 feet, most are 12 X 12.
ETA: If your mares are "due in a week" that means they could foal any time!! I hope you are keeping a close eye on them and will know when they are so close they must be watched CONSTANTLY.