Everybody has a system with all sorts of combinations of percentages of different chemicals. I've never used Windex, because the ammonia doesn't do anything more than plain water will do.
Here's what I've been doing for the last 40 years: mix up some super hot water and add a little bit of Dawn or other liquid soap in a short bucket.
Take off the barrel. For best water flow take out the nipple if it's a percussion cap gun, or the touch hole on a flintlock, but you can also leave them in if you want. On a flintlock touch hole or a rifle with a larger musket cap nipple it doesn't matter as much, it will just be a harder and take longer to push the water back through a smaller standard #11 nipple, so I always remove them.
Put the rifle breech down in the water (none of my BP rifles have removable breech plugs, which would make this even easier), and get a cleaning rod with a couple of thick patches on it.
Run the patches down to the bottom of the barrel, and suck the water mixture back up the barrel and back down a few times. You can pour the rest of the boiling water down the bore using a funnel if you want to chase it from the muzzle.
Pull the (hot!) barrel out of the bucket and wipe it down. It will dry super fast. Run a patch soaked with Ballistol or bore butter through the barrel (or Rem Oil or CLP or whatever you have). Wipe the outside of the barrel with whatever you used in the bore as well. You're done. I can clean 3 rifles in 10 minutes.
In the field I keep a little bottle of Ballistol and water and some patches to clean the worst of the fouling out of the bore. Some guys mix the Ballistol up to 10:1 with water, I just approximate 2 or 3:1 which I think works better.
No need for special concoctions IMNSHO. Hot water and a shot of liquid soap. I guess hot water and Murphy's would also work fine. If you don't have any soap, hot water alone will do a good job. I use this for Goex, 777, and Pyrodex, and the bores are pristine. Just be sure to treat the barrels after cleaning with hot water to prevent rust.