Seems like years ago I started my quest to do carbon transfer printing, After countless tissues and step tests it seemed I would never get past this stage. I could not even make a decent 21 step test print with pure black and a decent amount of highlights. Seemed I could get either a decent array of shadows or decent highlights, never both.
After two years of trying I eventually found a pigment loading that allowed me smooth transitional tones, which were not overly contrasty, I had also been way off on my Dichromate sensitizing.
I finally printed a carbon of my step test, which produced the full range of shadow and highlights, woo hoo! The values were all over the place, but I had something to work with.
Now to build that curve, unfortunately I don't use Adobe at all, just Paintshop Pro. which provides zilch in the way of help building a curve for a digital negative. I bought QTR, which did absolutely nothing to help, I did not understand it at all.
I then remembered Will Salley and his You Tube videos on making Digital Curves, although he does his in Adobe, it related across to Paintshop Pro and I finally had success.

So if you need to be breast fed, so to speak, try looking up Will Salley!