I ended up going with Track of the Wolf nipples, and therein lies a tale --
I went shootin' yesterday, only the 2nd time I have shot the Navy. I had the Track of the Wolf SS nipples installed, and I had procured both the recommended (by TotW) CCI #11 caps and some Remington #10s. In addition, I had purchased a 20 grain powder flask spout from TotW. 20 grains is the load I used during my first session.
My first concern was that I couldn't get the CCI caps onto the new nipples. There just wasn't quite enough clearance to let them turn that final corner. The Remingtons, due to their different construction, would go on to the nipples. So I used those. I measured the stock nipples and compared with TotW's listings and the PIR-LS ones looked closest, but maybe I should have got the PIR-S, which are .020" shorter.
The next concern was that the level of powder in the chamber looked higher than I remembered from the first session. I poured out the first load and refilled it. It looked the same, so I shrugged and proceeded (Churchill said that "Man sometimes stumbles across the truth, but usually gets up and continues on"). Newbie, right? Hmmm, recoil seems sharper than before. Must be OK, spout clearly says 20 grains. Shots were printing lower on the target, but I had filed the hammer slightly to correct for the high shots I was seeing before, so I congratulated myself on a successful modification. I fire about 25 rounds.
Later, found that the barrel wedge wouldn't come out. I struggled with it; eventually I had to get a small diameter steel rod and hammer it out. Then the barrel resisted coming off the arbor. The idea finally started to dawn that I was shooting a much heavier load. I weighed what the adjustable measure was throwing when set to 20 grains with the new spout. The "20 grain" spout was throwing 1/3 more powder, about 27 grains.
I hope I haven't damaged the revolver. Actually, pretty sure some metal movement occurred, just hope it wasn't too much. What do y'all think?
WIlTx, learning the hard way for 67 years ...