If you if you do the patching yourself here's a few tips I learned along the way:
Practice butt welding on scrap first and proceed when you are comfortable with your technique
Rather than trying to weld a bead, weld a series of spot welds by lifting the welding tip. This helps prevent burn through
Cut back to good solid metal.
Use some card stock and a sharpie to make a template.
Cut sheet metal slightly outside your trace lines and trim with snips to trim to a nice tight fit.
Test fit and trim this can be time consuming but take your time and be patient until you get it right.
Tight seams help prevent blow through and make for a nicer repair
I used small strong magnets where I couldn't clamp to hold butt weld in place and tacked with the welder.
Once I got 4 sides securely tacked, I started stitch welding. Do about 1/4" at a time and take your time.
Pause between stitches and wait for piece to cool to prevent warping
Alternate sides when stitch welding and again, wait for work to cool...important
Continue welding and waiting until patch is complete.
Takes some practice. Burn through was frustrating at first but with practice I got adequate enough with my technique to make it work.
