You probably won't get a lot of feedback on this subject because there are just a few breeders on this site, as this is primarily a pet forum.
I hadn't heard of the Misty Method, (I had to google it) but I do something very similar with my litters, as soon as they can eliminate on their own, and move purposefully, around 10 days to 2 weeks old. I designate a potty box (start with pee pads and introduce compressed paper cat litter pellets over a few days) as an area to pee and poop in, and the rest, where they eat, drink, sleep and play is kept very clean.
In fact, I wrote a potty box training article for a Facebook Reproduction group that was also published in a magazine a few years ago, my keeper puppies and pet puppies housebreak very quickly when they go home. I do use it as a positive selling point, because it is a lot more work to do it this way, than to put the puppies in a pen filled with shavings and they eliminate wherever/whenever, and are notoriously difficult to housebreak because they didn't learn to differentiate between clean and dirty.