I really like the idea of the big cube FI mill.... not sure how much your axles would like it tho...
just so it's in print somewhere...
late 80's, early 90's we went thru a stint where we did about a 1/2 dozen of the black jobs... there are various methods, but the simplest, most "not f*ckupable" way we found was just a straight black base job with varying percentages of pearl in the clear.. 5% is pretty subtle.. 10% gets more noticable.. did 2 69 Camaro's that way, one red and one gold... they came out pretty sick, especially the gold one..
you can also do it on a straight thru single stage, adding clear and pearl to your mix towards the end.. a much more difficult process.. on the 2 I did that way, I had to reshoot one.. but thats the chance you take doing something outside the box... in the end, they came awesome, little freakier looking than the base ones... but definitely not as easy to "control" the process...