Why don't you keep it all in the same therad?
There doesn't necessarily need to be a bonding wire. The panels are almost always constructed so that the grounding terminals are electrically connected to the case (though sometimes there may be a provision for removing that bonding, typically a screw or bar).

What did you use to make the connection to the case? The paint and even to some extent the rust will be a reasonable insulator. You need to find some place where you've got bare metal (I typically use the inside of one of the screw holes that previously had the cover screw in it).

I posted again as I wasn't sure I was asking the right question. Seemed easier to just start over.

I got your post on other. You were right about finding bare metal on box to test on. Yup....it's bonded to one of the bussbars.

Thanks again.