rethink janky thru-hull - advice?

[ohthetrees]

TLDR:
Does anyone know where to find a NPS bronze street elbow? The stores all seem to sell NPT only.

Long version:
I'm preparing a new-to-me Hanse 505 for delivery from Hawaii to Seattle. Both heads were experiencing frequent clogs, and I traced the problem to badly corroded metal plumbing and ball valve. The skin fitting appears to be plastic similar to a forespar product. I think the plumbing must not have been bronze, and big flakes of metal were occluding the pipe, and catching waste as it flowed through. When I removed the "bronze" elbow, I broke off the threads with my hands. When I get back to Seattle, and haul out, I intend to replace all the thru-hulls with TruDesign or bronze. In the mean time, I just want to get the boat safe for delivery back to Seattle.

I successfully replaced the plumbing in the forward head with a forespar marelon ball valve (which is the only NPS ball valve I know of) and bronze elbow, using the existing skin fitting, which seems in good shape.

My problem is now how to handle the aft head. I can't leave it, now that I know how rotten that metal likely is. So I have to replace the elbow and valve. But I don't like the current arrangement at all (see attached picture), with an elbow attached to the skin fitting before the valve. I think the valve should be last thing before the skin fitting. I suspect that this isn't how it came from the factory, the ball valve is different to the rest on the boat.

The problem is that I don't think a normal ball-valve would clear the cabinetry if I thread it straight onto the skin fitting, so I may be forced to have the elbow first. But the skin-fitting is likely NPS, and all elbows I've found are NPT.

OK, so then I'm forced to replicate the existing configuration. So I'm looking at:
skin fitting (NPS) --> 90º street elbow (NPS) --> Ball Valve (marelon NPS) --> Bronze Tail piece (NPS).

But at least at west marine, I'm not seeing any NPS elbows or NPS tail pieces.

Does anyone have any suggestions for how to put together a sensible arrangement? I'd prefer not to spend big money doing this since I'm going to be replacing it all when I haul out in Seattle.


Thanks in advance!