So there is not a lot to be done about the ~50% of sites where the IP is sufficient to identify the domain. For the others, where they suggest a heuristic base

So there is not a lot to be done about the ~50% of sites where the IP is sufficient to identify the domain. For the others, where they suggest a heuristic based on a PLF, it seems something like uMatrix (or a proxy based equivalent) could reduce, or change the fingerprint. Potentially at the cost of the page looking different (or ugly). I happen to use uMatrix simply to reduce b/w and make better use of my display (i.e. use the full width, not a silly narrow column), and most of the web is still usable. However such techniques would be beyond the likes of my parents and probably also my siblings.