I only apply the weld thru primer between the seems. I do not apply it over the outside of the seam prior to welding. Again, if you bump the current up one notch higher, the welder will easily overcome the zinc primer and creat nice welds.
You can see pictures of panel installation on my website on the Cuda Resto Pics page.
I dress my welds with a grinder and sander, then prime with PPG Epoxy to seal the weld and panel.
