Testing can get expensive, and I wouldn't rest easy with a carry pistol unless I had a few hundred consecutive rounds without incident. I second the recommendation on federal primers though. I have a m28 that someone did some trigger work on, and it is very light and smooth but is not reliable with anything but federal primers. With federal primers, I've never had a light strike.
I have a m17, one of my first S&W revolvers, that I had the local gun smith work on. He's fairly well known for rifle work in Florida, but not so much on pistol work. The 17 came back so light I cannot believe it is so reliable. The single action must be about 2 - 2.5 lbs, but I've never had a misfire; the double action is super low, too, and I will occasionally get a light strike, but it is rare.
I normally stone the rebound slide and install a 14# rebound spring, but often go to 15# when I don't like the feel of the return. I don't normally mess with much else as results are so varied, but I've done work on my two j-frame 22s, a model 35 and 63. Both got new springs and polishing. Both are far better than they were and both are as reliable as when I got them.