I remember spraying the 2001 first and mixed it high solids (4:2:1) to go 2 coat clear , the other mix ( 2:1:1 )was thinner and was a 3 coat clear, then the fist of the VOC laws came out and wasnt compliant anymore , so 2020 came out then another VOC rulling , and now we have the clears today.
Those clears are like spraying Karo syirup ..LOL
You have to have an HVLP gun , with a mountain of air supply to spray them.
WOW i forgot all about using that NCT it was very fast , but had that yellow tint you speak of , and i didnt use it much as it sucked for spots as it changed the color when sprayed. (whites went a yellow cast)Plus it didnt last very long either.

Have you been able to go to the PPG paint schools?
I have been to a ton of them , plus I have to keep up my all levels as our shop is a platinum PPG shop .
The DRR reactive reducer is good for 1 month after its opened. maybe longer if kept in a cool place.

Walt, i wished you did too, as i would like to help you :-)