some of my current tools, for @carocrow to see. I use the black rubber erasers, they're softer. a squishy mechanical pencil, and a pack of soft .09 leads. I prefer the thicker lead, they don't break when I push hard, and I tend to push hard.
Also in the image is a prismacolor brush marker, and a gel pen. I've been using a 6-round nib, in a dip pen, with FW water-resistant ink for these so far but I may switch over to one of these other pens, possibly the gel. I'm looking for more line consistency than I'm getting out of the nib pen.
These are for a production product that is now copyright so I can't discuss it until it comes out in print (although I CAN post progress shots of some of the work I'm doing on it!)