Zongshen 200GY-A, rehab exhaust question

[tankme]

Originally Posted by Weldangrind

Also, your header has the dreaded catalytic converter in it, and you could scribe a reference line across the length, cut it open, gut it and weld it back up. You'd need to remove all of the rust first.

Is the red line where I should halve it?

Is there a preferred way to cut it? I can hacksaw it to lose the least amount of kerf, or chop saw it if it doesn't matter. I've never gutted a cc this small and it should prove interesting. I'll even post pics!

Thanks for the direction!
Jim