I have always replaced mine as the factory intended. If sectioning a rocker I would suggest more than a lap weld. It should have a full backer with plug welds and a solid weld. You can access them for corrosion protection with a wand from the front or rear. I personally wouldnt section a rocker on a classic car... although we do it daily in the collision world it has to be in certain locations specified my the Oem.