@darius I haven't studied this formally but the general sense I've gotten is that "attempt to anticipate all accessibility needs ahead of time" is an anti-pattern.

Most of what I've seen has emphasized, where possible, giving users the flexibility to set their own environments to be accessible, and putting effort to ensure the document or application doesn't break when changing -- and provides enough control points to change it in the first place -- in those ranges, rather than a discrete set of set paths.