That was some great analysis and effort done to share your personal research with us.
After weighing the charges, did you happen to notice whether the Swiss was 10% - 11% denser by volume compared to the Goex as it has been suggested?
If not that much denser, then did you note how much denser it was by volume?
The Swiss powder is said to be a moister powder which in part increases it's potency.
And that moisture is also thought to promote a softer fouling residue.
That might not be notable unless humidity becomes a factor in some locations during a humid time of the year.
Also, I'm not sure if the Swiss powder is screened to the same size granulation as the Goex powder..
Could that be why Swiss is made in the 1.5 granulation, and could that be more comparable to 2F Goex than 2F Swiss is?
I recently read a report which measured the speed of pan or priming powders for flintlocks
I had never heard of Swiss Null B before, but the report indicated that Swiss Null B was measured to be a slightly faster priming powder than even Swiss 4F.
Yet it's reputed to be floor sweepings leftover from making all of the other granulations.
Here's the article:--->>>
https://www.blackpowdermag.com/priming-powder-timing/
Since you're testing a fast twist barrel, it would also be interesting to see if there were any significant accuracy differences using sabots.
One has to wonder whether some bullets [sabots] or projectiles would benefit more from the increased velocity of Swiss than others, as opposed to the bore size conicals.
I realize that's asking too much, especially since you made it clear that the test results were very specific for the bullet & load that you were testing, and conicals are what you like to shoot.
I bought some Swiss myself just to have some, but never actually loaded any black powder for my own use, making my own interest only academic, at least for now.
Thanks for sharing all of your effort.