Thanks Jim! I wasn't familiar with "cascading" VCAs, and looked into it. Looks like I can treat a section of it as a simple unity mixer, so that helps to mix another voice in!
I took out the Plaits and 2HP Mix for now and added a Veils clone. I'm gonna leave 20hp blank for now until I get everything received and figure out whether I really need another voice, more utility modules, etc etc.