I see the injection elbow now.

Thanks on the Centrek mufflers, better and cheaper. I have no need of the swivel action of the Vetus. One of those, a hamilton injection elbow, a handful of pipe fittings, some hose, clamps, and I'm done.

I'll watch how much heft I get in the riser but I don't think there will be much iron in it. Probably a street elbow, one length 2" pipe, and the injection elbow(alt: another elbow and a nipple to the injection elbow).