So I did make a mistake here. I was actually on 6995 even though I thought I was on 6996. However, if the release notes for 6996 mentioned a major fix to graylisting (since lots of mail wasn't even being delivered, or simply delayed for many many hours) it sure would have raised a flag.
Anyway, 6996 seems to have cleared my issues with mail delivery. Although, I am unsure how to completely confirm that. I mentioned in my ticket that I would like to have a UI for graylisting that shows email addresses and their associated wait times, time to expire, etc. And from there, we could whitelist, blacklist, etc. Logs are great, but sometimes I don't have time to dig that deep.
I would also like to mention that ST support has been as good to me, if not better than ever. I appreciate that. That being said, if you have a problem, open a ticket. I feel as though that is what they prioritize, and rightfully so, over the community forums.