Vertical card compass installation

I am not sure how the one that they call out for the Ercoupe mounts. It looks like it takes vertical screws and nuts. That would be ok for a bubble windshield but not for a flat one. I usually use one of the center window mounts that they advertise with the horizontal screws and nuts. Also realize there are two different windshield braces in Ercoupe. Some are solid aluminum and some are hollow steel square tubing. I would not mount in either case with pulled rivets.

Considering a vertical card compass. Had one in my RV and liked it. Aircraft spruce has a Ercoupe custom mount for the compass that mounts to the windshield stringer. Looks like I may have to install the hanger to the stringer wilth aluminum pulled rivets. Anyone else been down this road and have thoughts to share?