I'll try making another profile using the generic canvas preset before I start working with the second print I need to do and see if it comes any closer. Thanks for the tip. I have to wait a few days until a new 17" roll of Lyve shows up to play on.
As far as soft proofing goes, I gave up on that years ago. Every new version of Photoshop that comes out gets a few tries to see if it's any more useful than the previous version, and it never is. Saturation has always been too conservative. It will give you an idea of where to look for issues on a test print, but that's about it. I never make changes to my master file based on soft proofing.