I would make a different slant on it:
inasmuch as this is a highly individualized game, what works well for other might or might not do for you: but it's a good starting point.
I would get a small bag of some sort, which you can easily carry (a small or medium purse at the Goodwill can get you started ... you can bust it up and use the leather for later on). ... fill this with the stuff you think you'll need, and then go to the range with (in addition to the other stuff) a notebook and a pen. WRITE DOWN the tools you use, as you reload and shoot and clean. If there's something you didn't bring, make note of that, too.
Then simply take the stuff you don't use out of the bag. Repeat this process a half dozen times, and you'll have a pretty efficient bag list.
then, take the purse and make a bag about the same size in a style that you find appealing. For good instructions on how to make a bag, check out this book:
https://www.trackofthewolf.com/Categories/PartDetail.aspx/49/1/BOOK-R18-CHP
Recreating the 18th Century Hunting Pouch is not that expensive, considering the knowledge you get, and the whole project shouldn't set you back any more than the cost of a new pouch
but
you will have the knowledge
you will have the skill set
you will have the book
you will have the tools (ironically, my pouch tools are now in the tackle box which once held the shooting stuff)
you will have a pouch of your own making (remember, the coolest tools are the one you make for yourself)
now, when you get your next muzzle loader, you can make a bag specifically for
that gun and, in the fullness of time, you will have a pouch for each gun, and you will have joined the realm of the cool guys.
Good luck with your project, and Make Good Smoke!