If you are interested by the history behind them, two great channels I follow on youtube are
https://www.youtube.com/user/capandball and
https://www.youtube.com/user/duelist1954
Here is a video on how to make your own paper cartridge:
I've tried all the variation and all the possible ways shown on Internet and read in magazines, but for me, the simplest of all those method is also the one I have the most success with. Load each chamber from a powder measure, put a lubricated felt wad (or if you are cheap like me a lubricated fiber or cardboard wad or even nothing) and a round ball to top it off.
I've never had any chain fire, which contrary to belief most often come from ill fitted cap and not from the chamber mouth. If you use correct ball size, they will fit so tight in the chamber that it is impossible to get a spark in there from the mouth of the chamber. If you put grease over mouth, you will see that after a couple shots, all that grease is melted and not sealing the remaining chambers anyway. It keep the fouling soft tough, so you can shoot more cylinder before it start to bind. I do not think they ever greased the mouth in the old time, it is a mess by hot day and would have been impractical for soldiers of those times.
I've also tried with various filler, like corn meal, to seat the ball as close to the chamber mouth as possible, but never saw any difference in accuracy.
It is a lot of fun to try all you read and see, but in the end, use what work best for you.