[CocoaSpud]

Try loading the mirror as a door layer, with the wall layer separate. I think that will solve the repeat problem. The walls/overlays get repeated as needed to fill gaps, while the doors do not. It's the UA does it too.

There is a guy who has started to work out a format that uses 7 distant walls rather than 5. This would create a better perspective and avoid the repeated walls. This format is still under construction though.