Hello there, @MichaelBurville ...
Thanks for your question. It sounds as though you have two parts to your rubric for this peer review assignment. Part of your rubric you normally use for the assignment, but then you also have another part which will include the peer review items that your students will provide feedback on. As you may know, you can only attach one rubric on a given assignment in Canvas. And, I'm guessing that you've already reviewed this Guide:
How do I view student peer review comments as an i... - Instructure Community (canvaslms.com)
Keeping in mind that my role in Canvas has been an administrator and not so much an instructor, I would recommend that you maybe split up your assignment into two parts. This would create two separate assignments in your Gradebook, and I know this might not be the most idea. However, if you split up the assignment into two parts, you can essentially attach one rubric per assignment and give them the proper points for each part of the assignment ... while also taking advantage of the peer review for only the second part of the assignment. You could set this up in your Modules page so that you'd want your students to first review/complete the assignment in the first one, and then go to the second part for the peer review.
I know this suggestion might not be the most ideal or the only way to do things...and I imagine there might be other instructors here in the Community that have had more experience with this than I have. But, this is the first thing that came to mind as I was reading through your posting. My $0.02 ... for what it's worth. Hope it will help in some way ... or at least spark some ideas for you to try. Good luck!