Roof oil canning

[79vette]

So I realize I probably should have asked her before doing anything, but I didn't and now I need to fix my mistakes.

I have an 88 square body with some rust in the outer roof skin due to leaking cab clearance lights. I cut the rusty sections out and fit patch panels as tight as I could. They tacked up fine but after welding the first one up (largest one on the driver side) I now have pretty bad oil canning in the driver side of the roof. I tried to go slow and move around, but apparently it wasn't enough. Since this truck has a 2 piece roof it is not possible to planish the welds since there is no access from the inside.

My question is what should I do at this point, and how should have I approached this repair in the first place? I do not have a stud welder, and I even if I did I'm not a body guy and I suspect I would just make things worse.

I'm assuming the welds shrinking have pulled the panel causing the oil can. If I cut out the patch, hopefully it will relieve the stress and the roof will return to its previous shape and I'll be back where I started with a slightly bigger hole.

Is it possible for an amateur to weld patches like this with a mig and not have it oil can? Or is the roof too flat and unsupported for it to work without being able to planish the welds? If welding isn't going to work can I cut out the patches, make new ones, and put it together with panel adhesive? Once I make new patches I could cut another piece to match the perimeter of the patch with a 0.75" offset on each side and bond it to the bottom of the roof with panel adhesive. Once cured I could bond the patch to that "lip" to achieve a flush repair.

I appreciate any advice you may have