Followed your lead, silver soldered, Bfit did required turning out of the brass fittings, and did the brazing.
Looks very good, I'll post a pic tomorrow once I have it washed out. If I bring it out now "somebody" will get angry.
I disagree with ordinary coolant - we now have steel, brass, cast iron and aluminium, throw in water or any coolant with irregular pH's and I tink corrosion will run rampant, I will be coating inside of brass, and consider a "Waterless" coolant, saw same on Wheeler Dealers, might be the go, depends on cost,.
I cant thank Bfit enough for his more than able assistance with this issue.