I had to google "dry denim" just to figure out what was going on here.
I think I bought a pair of these jeans once by mistake because the indigo dye kept rubbing off on things until I washed them a few times in a row. I am surprised to learn that people really wear a pair of pants for 6 months without washing them when they are not homeless or something. Hell, I lived in the woods for a year and managed to wash my pants once a week in a stream.
Anyway, I have a b-17 in honey which has darkened nicely over time. Why don't you just grab a saddle cover? They you can cover up the brooks while you ride it with these special pants, and uncover when you are wearing regular pants.