How to repair wire gutter?

[rechinca]

Found one of my cab leaks. Under the seam sealer in the wire gutter I have the ugly scene below. Several small holes through the stacked seam of the cowl/firewall. I know the best would be to cut out a small section and lay in the fresh patch. But I’ll be honest, I just got my welder and really don’t know my ability to tackle this narrowed area. Is it possible to hold the copper spoon/flattened pipe below it and do several small tacks to fill it? I may have to pay a guy to tackle it in my driveway for the time being. I’ll take any suggestions short of just covering it with crap for the time being. Plus the added factor of I don’t really want to gut my dash, although short of the inner heater box, controls and radio everything else is already removed.