A fade will be that much easier if you can switch congregations. If you "forget" to make the switch official, it will add to the confusion. Just start attending some meetings with the other congregation, and make sure you don't establish a pattern that's easy to figure out
This is exactly what worked for me! When I moved away, I never even bothered to have my record card transferred. I attended a couple meetings in the new area and the Service Overseer made up a temporary card for me. Within that very month I simply stopped attending. I believe each congregation had assumed I went to the other.