I dont want any filler, so I fit each part perfectly with a butt joint, dolly it out where possible, then grind it flat and smooth for an original fit. before any welding I prime all parts on the back side and pinch points with weld-thru primer
the arc and inner rocker are new in this picture
then the rear of the rocker, putting back the spot welds in the OEM position
Some more primer to look super clean and blend in tot he original rocker which was perfect everywhere else
Finally fit the outer skin and tig it in small steps so no warping
Some more smoothing of the welds and original spotweld locations used
Just a small skim coat of filler on the upper weld seem, but making sure to leave all the factory spot welds to show through the paint.
Other side is the same, so on to the front fender next