When I restore a Escort bubble area :
I drill out the spot welds with a spot weld drill and use a brickies chisel which is wide yet narrow and split the panels apart,
I weld up all rust damage and also any drilled through spot welds,
I then piant under where the bubble goes with black gloss por15 and reseal the seams around the fan hole,
I put the bubble back on useing panel bonding glue which is used in todays smash repair shops when replacing a modern day car glued on panel
No distortion ,very little clean up and when the glue comes out of the drilled holes of the bubble,it looks like factory spot welds