I did the 'ATF' thing. I had a half quart I dumped into it with nearly fresh oil to start with. It seemed to help slightly. I think the only way to remedy it is a cam and lifter replacement. Then you start doing stuff like a new timing chain and sprockets, and, and.... know what I mean....
Not much has been said about how long the 'diesel sounding top ends' will last once they get noisy, but I'm gathering they will go a while still latteling and noisy.