I got the final end cap welded on today, not the neatest tig weld due to my poor cutting of that end of the can. No filler was used in the weld, just flowing the parent material. I gave the muffler a quick once over with a cup wire brush on the angle grinder. I think this is as far as I am going with the finish, I don’t see myself holding the thing up to the buffing wheel for a couple of hours.
The pics show the muffler sitting on some aluminum off cuts ( I have access to a lot of interesting shapes in various thicknesses of aluminum, remnants from water jet cutting of work parts). These scrap bits had curves to match the radius of the muffler. The scrap is clamped to a spare engine mount casting so I can see how I need to move things and what metal to remove. I’m leaning towards the aluminum supports (yes David, there will be electrolysis where the ss and Al touch:)) with some T-bolt ss straps holding the muffler tight.