I have at leas 8 different calibers to deal with. Not all the same gun of coarse. Just takes some sorting. I have my supplies in a tackle box to keep the different sizes sorted in different bins.
Keep good notes - load, powder, rods, caps, flints etc..... etc.....
My gun-caliber lists I keep in my MEMO software on my phone.
When I go muzzling I refer to my notes.
I plan my range trips with a 100 round supply stock, and normally only take 1 gun at a time.
I then put the appropriate ball, patch, rod, powder, flask, etc....... into the range box.
When I get back and finish cleaning, I restock the supplies that I used.
Refill the windex wipe bottle,
Refill the MAP cleaning bottle,
Replenish the container of round patches,
Replenish the patches tin(s)
Replenish the powder flask(s)
Replenish the cap strippers or flint wallet,
Refill the ball ball\box from the bulk container,
Put everything away in the cabinets so the next trip out will be just putting the supplies off the list for that gun in the range box.
It does take some time to get it all organized but once you get your lists made it's fast and easy.
I have also made checklists like this for a hunting trip, loading my bag with the supplies I will need instead of the range box. The big difference is the quantity of supplies. A hunting trip is normally based on a 10 ball trip for large game and a 25 ball trip for small game.