Another good book (actually kinda the bible) is 'Metal Bumping' by (something, Frank?) Sargent. It was written back in the forties and the info is timeless, it'll show you how to move the metal around so that you just use a skim coat if any filler at all.
It is obvious that you want to do as good a job as possible, you really don't want to tackweld a patch panel and slather it over with fillers - that won't get you bragging rights will it, it'll just get you the car that you wouldn't want to buy. Some of the more recent bodyworking books detail more modern techniques working with adhesives and high tensile steel, these techniques are acceptable for 'industry standards' but you are working on a hot rod and it is all about craftsmanship. When you spring for a Martin body hammer and dolley and use it for the first time you will recongize that it is a fine instrument and not just an expensive hammer. For the next couple years you'll kearn to get good enough to use that hammer. And that is what hot rodding is all about.