8hrs cooldown still works for any SSID, but with NZ@McD1 you may not change MAC at all and still will have a streetpass every 8 hours. That is because european Nintnendo access points with streetpass relays are spreading streetpass data between relays, like in Streetpass Weekends in the US, and do not check MAC, so you can get streetpass with any MAC.
Using attwifi reqires to switch off wireless security, wich is impossible in Windows with most of the drivers. There is no need to stick with attwifi on Windows anyway because of the first octet limitation in Windows - you can't set official Nintendo Zone access point MACs so it's not use for attwifi at all, while with NZ@McD1 you'e not limited with the secirity.
You can follow "Before you tried anything else" link at the first post of the topic and not worry about any nintendo zone rules changes anymore.