Basically speaking you never need to weld on the replacement rocker panels. Just cut out and clean up the rusted area. Cut out all the rust and get inside and wire brush grind , sand what ever you need to do to get the new panel to fit snug on the lower rocker, sill area or inner if you need both. You can use urethane adhesive and 3/16" rivets to fasten the rocker over top of the OEM rocker. Use Rust reformer inside and out seal the edges with seam sealer , prime and paint. If you are trying to restore it perfect you are on your own. I did that in the past but do not get that fussy anymore. I am restiqueing at this point these are survivors and not trailer queens. To each his own. My field repairs look good and last for years. Have at it you can do the same. Easy to do and touch up as needed. My opinion on this matter. Been there and done it several times.
