simply ground the other wire to the frame.
i dunno about no exhaust gasket & sealer only...it might be fine if you keep a close eye on the tightness until it gets a chance to bake in. i think if it starts to leak, tho, it will always leak. that's just my exhaust mechanic's opinion, let us know how it holds up
hey, joe, this has been a fun thread to read thru, & i think you've done a great job on the build. i hope other people want to declare "project topic" status as it was also really easy to moderate 8)