So I did as stated on the packaging and applied a new layer for 6 days without taking it off or putting on polish, and then I had to remove the chippy mess on day 6 and put on a fresh layer.
My peels have not got bigger and my nails feel stronger, but I think I need some more moisture, because Nu Nail is very drying as you can see from the picture. My nails are very clean looking however - almost all of the staining is gone! I could actually put on a sheer polish and get away with it...
I would give Nu Nails 4 out of 5 stars. It doesn't contain any of the big 3 nasties, so it's definitely a good alternative to some of the other nail strengtheners.
I am going to use Sally Hansen Nail Quencher as base coat to today's manicure to lock in some moisture, but I can't decide which colour to put on so you'll have to wait for the NOTD :)