I only replicate mullered borders on old patterns I re-cut. I think they were popular back in the day because they can be a device to camouflage minor boo boos on borders created by harried checkerers in factory settings. I do also think they add a touch of elegance on new custom jobs, but that may be a result of my fondness for old pieces.
The couple of times I incorporated mullered borders on fresh panels I first established my borders then cut the mullered borders to about half depth, and then proceeded to fill in the patterns. After that was done I finally took the borders down to full depth. That allowed me to have a distinct border to work up to and made the mullering easier to accomplish. I don't know if that's the correct protocol but it worked for me. It still made for a lot of touching up/completing those little tiny partial diamonds along curved borders but that is the devil of it in any style of checkering, at least to me anyway.
