These look fantastic.. I have always loved this mountain style on old maps... but it take patience.
I've been trying to make convincing looking Photoshop brushes too, messing with all the brush tool settings for size and angle jitter and roundness ... Looks like Illustrator makes it work better. Don't have it, so will keep trying to make PS work somehow. I was thinking maybe 3 or 4 different brushes, with wide spacing, and stroke them all over the same path... might make it a bit more random looking. or a bot too random looking. ... who knows!