Alan, I am really looking forward to your finished product! Has to be a labor of love for you to tackle this, regardless of age. So, I'm nowhere near the authority the Thomas brothers or others on this forum are, but I've always found it of interest that generally speaking, it is not unusual for either revolver or carbine bullets to have a larger diameter than the caliber. This goes back to the McKee and Mason books, where diameters of some of the calibers also show similar patterns to what you are describing with Tom Stelma's and the T&T references. In fact, while I am away from my reference library, I'd suggest M&M would say your example is a .31 caliber.
Some bullets, particularly those field cast, show great variation in measurements. That has to be kept in mind. Having said that, as much as you can, I'd suggest RBTRF to be the final arbiter on the subject. I respectfully disagree with a couple of statements in them, but nowhere else is there as well researched body of work.
Many of the bullet names go back to M&M or for Trans-Mississippi bullets, to those that were first to document the bullets in print with catchy names like "the Arkansas Hog". Lot more memorable than the "Mangeot" name attached to M&M 608 - yet the bullets are one and the same.
Again, I'm looking forward to your finished product! I suspect it will generate discussion and provide clarity.