For posterity's sake...
That bracket inside looked like it should have been secured, so it was welded first:
I never claimed to be good at it...
Tack the patch on, shape it to the tunnel
Make a relief cut so it sits better
Warm up the dryer circuit breaker a bit more
Yep. Sums it up.
as it sits, waiting for me to patch the other hole, then lay on the Herculiner
P O wasn't hesitant about cutting into the tunnel...
This is where I had to stop
Thunderstorm rolled in, several lightning strikes in the neighborhood. Photobucket isn't showing the pic for whatever reason.