Thanks for the update. Very interesting.
I do have one comment about the 19.8 gr. of 2400 being "below published max." The last freebie reloading guide I have from Alliant is from 1995, but it lists 20.6 gr. for a 240 lead gas checked bullet and 18.7 gr. for a 240 JSP. In my experience (from several handguns only, no rifles) the 20.7 gr. is excessive and gives me hard stuck cases in everything from my Smiths to my Super Blackhawk. In very hot weather, even 19.0 gr. was too much with lead bullets (plain based). Every load/gun combo is a law unto itself.
Best wishes on your continued success.