Put a tilt EQ or maybe a weighting filter in your monitor FX chain to boost the highs while mixing, that way you might be less prone to boost the highs in the mix too much. This EQ/filter won't be affecting your master, just what your monitoring. Reaper has a dedicated monitor FX chain, in Cubase I think it's called control room, other DAW's should have something like this as well.

 

all that crackling and poping does create a sense of nostalgia, but it just gets distracting after a while. that is one hell of a trashed record. i would suggest it has to be automated, either mutes or faded in and out like any other musical element. other than that it sounds fine. if you are happy with it, and you can get the client to sign off on it, it is all good.

one good thing about the new workflows is that you can try a lot of things out in a short amount of time. you can experiment and not lose much time. you can also template ideas that work, if you like that workflow.

 

Basically, you killed the soulful warm body of the original which seperates the low end from his uprange voice nicely which creates space. My suggestion would be to not master using headphones