I have a two-spot job that uses a Pantone Blue C and a Pantone Black C. I need to create various tints of the black spot, but I don't really like using Pantone blacks for tints. From a production standpoint, would it matter if I substituted Black C for a CMYK 100% K value (process black)?
There's no reason you can't use a standard process black in place of Pantone black. You're the designer, it's your call. You'll just want to be sure the overall tone of the printer's ink is what you're after. Pantone has their own special formula to achieve a certain subtle tonality.