Ned, as per our discussion, I tried the two-into-one configuration 1st with my stock catalytic converter can and SAS. Bike ran smoothly, but seemed a little "constipated", and the engine ran hotter then usual, with all the exhaust going through one catalytic converter. So Stage I testing not satisfactory.
Stage II was after having my blacksmith, Smithy 1, core out the center of the catalytic converter, again keeping the SAS and stock jetting. The bike runs BEAUTIFULLY! Very powerful through all RPMs. No surging anymore (had a little before at constant speeds). Engine running normal temperature, and the can no longer "glows". Even with the baffles retained, the stock can, with the converter cored, flows freely.
And, quiet as a mouse, because we left the baffles in the can. Good for stealth dirt rides in the woods!
So, for now, I'm happy. I have room for your reserve gas container, or the one the Smithy 1 is making for me.
Stage III, which was to get a single after-market exhaust, doesn't look necessary for me, since I like the way the stock can looks, and it works like a bumper, it's so strong.