Like you, I have been wet tumbling all me reloads for (more than) ten years and have been happy with the results at all times. My experience varies a little, but as you say, likely several different methods work.So, how to get the best results with the least damage to the cases:
1. Don't overfill the drum with cases (Lyman suggests half full)
2. Don't overfill the drum with water (Lyman suggests just enough to cover the cases)
3. Most tumblers come with 5 pounds of media. Use it all.
4. Limit tumbling time (a absolute maximum of 90 minutes should clean the dirtiest of cases)
Now I'm not saying anyone's method is wrong but what I can tell you is that this is how I have done it and I've been wet tumbling for probably 10 years and have never had a problem with insufficiently clean cases or peened case mouths so I must be doing something right.
1. I don't overfill the tumbler with cases. Never count them, but half full is likely the usual.
2. I fill the tumbler right to the top with water, virtually no air space.
3. I use the 5 lbs of pins that I originally bought, can't recall where, I didn't buy with tumbler.
4. I always tumble at least 4 hours, sometimes longer when I get distracted. (Can't recall if I came up with this because a batch wasn't clean enough earlier, or if it's just an arbitrary habit. Also I believe my tumbler turns somewhat slower than others I have seen.)
I use Tide laundry detergent and citric acid crystals.
I have never observed any peening, ever.
Another little lesson I learned early: mixing different sized cases can be problematic. Once did a batch of 50BMG and something small, think it was 223. Had a bunch of the small cases stuck inside the big ones and jammed with pins. A ##### to separate.
I am going to get some SS balls and try it. Seems no matter what I try, I always fight with a few pins dried into brass at some point,



















































