Rust pin holes on roof

[Kieron g]

Hi BX people. Gradually getting through the jobs on my 1.6 RS.
I noticed some tiny bubbles on the roof panel just in front of the sunroof.
Of course when poked they go through.
Thinking ahead when I get car mot'd and home I'll need to tackle this.
I've seen a good YouTube post where someone does a similar repair on a Mercedes with their mig set using magnets to hold a flat strip of brass under the repair area.
My worry is distortion, I appreciate the use of low amps and just spots of weld to reduce heat build up but the roof panel looks so thin.
I have a dremmal type tool which I can use to enlarge the holes to remove the rust.
Can anyone advise if they have attempted a similar repair and how they managed it.
Thanks

[Kieron g]

Investigated this further and will need the front edge where sunroof closes cutting out on N/S so will have to fit a piece in I think not just spot welding a few holes.