I believe this is completed! I have spent a few hours tweaking it and looking at it in greyscale, so I think it's okay. Just need to hear back from my client and get his okay before I begin spraying.
This painting will get two layers of permanent fixative, then three layers of varnish before it is ready to be handed over to my client. It's better to do all of that spraying over the course of at least two days, so I need to begin it ASAP so he can get the portrait on time. I am awaiting my client's approval so I can begin spraying.