You DONT want to spot weld your new pan.....2 reasons...: 1, you'll NEVER
obtain a spot welder to do the job correctly, 2: theres no reason why you
cant use existing equipment to perform the task, even 110 equipment.
Fit your pans so they lye in correctly, from the underside side scribe a line
against your unibodies exterior seam.........measure 'in' and down that seam
the length of the repair 3/16" of an in....drill a 1/4" hole every 2.5-3", plug
weld each hole from the center out.
If you have questions about any other areas as far as correct welding goes,
ask....Im sure someone will reply with tips!