Jock, after tack welding into place did you go back and fill the rest with the welder or with other filler material? Thanks.
I just took pics of the initial tacking, but went on to completely weld the seam,skipping around to avoid heat build up and/or warpage.
I then 'dressed the weld with a 40grit 'soft' disc,again skipping around and finally a
thin skim of bondo.
My metal working skills don't quite stretch to planishing and metal finishing yet!
Above all else be patient,and take time with the welding.