Thanks for the feedback. So it's just a coincidence that the Liquitex Mixing White has lead in it. (I thought that was outlawed in 1978...) Their web site doesn't say anything about lead, though it does have warning about spraying cadmium pigments. I suspect the amount of lead is tiny since it's not the base pigment, but I'll research other brands too.
I have had very good results with your dust brew in minimal fade applications. I probably went too fast in the heavier tests. My brew definitely takes lots of coats too but now I barely pull back on the trigger to keep the flow down (with pressure in the high teens). At those low rates, one can basically overcoat almost continuously.
You're exactly right about the flat finish of the Dust. That makes an excellent substrate for the subsequent washes to "flow like oil". I'm a bit worried that my brew is not flat enough for good wash performance, but I'll soon see. If not, maybe adding a bit of dust to it will help.
You're also exactly right about the cooling effect of a white fade. My first test of this stuff was on an old Atlas UP hopper with a rather extreme brown:
The lavender cast in the faded section is quite obvious, though it's much less so in lower lighting. I'm guessing that a transparent admixture of the base color would help (if it didn't ruin the lettering color).
Cheers,
Gary