Dan-- I really think it's time you invest in a RIP-- the amount of effort you are putting into things that would be easily solved (or at least solvable) by having a program with true full control over your machines would be a gamechanger for you IMO. Take a look at mirage, it's really got a great interface and isn't insanely expensive or complicated like some of the other options out there.
I've made a fantastic approximation of Epson's ABW mode on a canon in Ergosoft-- basically ABW limits the printer to using all the black inks, and then eliminates all other colors except for light magenta, light cyan, and yellow, and it limits the ink outputs on these 3 color channels pretty dramatically-- this gives it the ability to still tone prints subtly without the color shifting so drastically with small moves made in PS or whatever image processing program you use (or in the ABW driver itself).
For the vast majority of black and white prints I run on my ipf9400s I still use RGB profiles-- I make them thru i1profiler, and the results are really quite good, but the manual "faux ABW" mode is on another level.
Color management really is an incredibly deep and complex topic, but it can be very interesting, and even fun once you get past the mental image of these machines having any kind of intelligence as to what it is they're doing when producing a pleasing image on paper. The printer manufacturers have long touted their products as being "just hit print" devices, but the amount of effort in engineering to get them even somewhat close to that point is immense. But also what it boils down to in the end is a pretty simple concept-- we've got a bunch of hoses containing different colors of ink turning on and off at different times in an attempt to create a huge range of colors out of a comparatively small sample set. The journey from concept to execution is where all the magic (and all the hassle) happens.
