I was thinking about the NV55. how does it compare to the SS-4MA?
I haven't used either one of them so far, so I couldn't say. I am still building my first regulator also.
Both the NV55 and NV55-18 are good products from all I have read. They will likely require no adapters depending on your regulator. This is a low flow needle valve as well.
The SS-4MA I mentioned is very much like the
SS-4MA-MH but without the Vernier Handle. It is a medium flow needle valve. Not as good for our use most likely, but I'm going to try it out just because it was cheap. It also has tube fittings which would require you buy adapters to fit it to your npt connections. Its original cost from the dealer is around $90. I only mentioned it because they are a good deal at $35
I really can't say what is the best, I haven't used them yet. On a budget and going for reliability with no question of quality.. I'd buy the NV55. The other was just a suggestion if you wanted to experiment with it. I am personally going to use a Parker H3L