I have no means of helping you with the DOM of your 17. But I will offer some suggestions with regard to favorite/cleanest ammo. I have a nice M-18 that has worked superlatively with every .22LR ammo that I have ever tried in it. In terms of favorite, my favorite is whatever .22 LR I can find available for sale at anything other than scalper prices. As I live in a rural area, there are few places that sell ammo. So I buy what I can when I find it. In my area even Wal-Mart has not had very much .22 LR ammo available. In terms of cleanest ammo, I have generally found that the various types of copper washed or plated .22 LR ammo gave the cleanest results in my M-18. For extended shooting sessions I have found it helpful to bring a cleaning rod with a bronze brush, patches and jag and some bore cleaner in my range bag. At some point given that I fire a lot of rounds, I find it useful to brush/patch out the little bits of grease/powder fouling, etc. that build up in the chambers of the cylinder, under the extractor star and on the recoil shield around the firing pin hole. Especially when firing in double-action it makes the revolver operate more easily and allows me to get better on target results.
Your 17 is a fine example of some of the best that S&W has ever produced. You and your revolver are due to have many happy times at the range and in the woods. Sincerely. Brucev.