What's the best way to get from stainless 1½"FPT to brass 1¼"FPT?

[JohnDS]

I am trying to reduce from Navien part #: 30026576B to Navien part #: GXXX001727 making it as clean and simple as possible. Most of this install will be pro press. See photos below.

So I need to reduce 3 times:
1) 1½" fpt stainless to 1¼" fpt brass.
2) 1¼" fpt brass to 3/4" brass female press fitting.
3) 1½" fpt stainless to 3/4" copper female press fittIng.

 

[Twowaxhack]

Use some brass bell reducers or whatever’s called for. I don’t see the big deal here.