Thanks to a helpful walkthrough by Matthew Kean and some elbow grease, I learned UVLayout throughout the process of this unwrap. Being able to manage UVs in a new way has been exciting and I’m eager to make more use of it.
As become my regular workflow, I packed the UV sets using IPackThat and set up SGs in Max with the Smoothing-Groups-From-UV-Islands script by Martin Palko.
The unwrap is complete, using two and a half 4k maps. Largest texture project I’ve attempted. Should be fun!