JOG is the only person I heard say they removed the inner pipe for similar reasons.

I mentioned this on your FB post - the amount of carbon deposits in your exhaust will contaminate the welds.  It will be extremely difficult to get the metal clean enough to get a weld that will last.  You would be better off getting a replacement header pipe.  It may not be the cheapest solution, but it will be the one that lasts the longest.

It's Not easy to remove. Gotta slice and dice the header. If you do that, you have to leave indexing marks to keep the orientation of the ends of the header aligned as it is built.
I don't recommend it. Wouldn't do it again. But mine was working fine. In Your position, yeah, if you can get it tigged back together cheap enough, cut the thing out, unless it's just busted loose at the end or ends, then anyone with a min can put it back together.
A body shop has a mig. Talking about a five minute job, a Coupla six packs otta get it.