Not really (to both).
In some cases, using RGB with a PostScript (emulated) printer, or using CMYK with a non PostScript printer (through a PDF), you may get an unexpected outcome.
So you're suggesting I stick with percentages of CMYK black (K)?
I am, Steve.
I believe you should use the BR-Script3 emulation driver if printing as an AI file (I just looked it up).
Thanks, I actually set that up since AI info said something about working with Postscript printers, so I figured it would work better with BR-Script3 than CUPS.
You are welcome, Steve.