Bob, I can't imagine why the edge welding method would go out the window simply because the master and his gang aren't fast enuf. Hammers can't be ganged, made into shaped swages, powered by hydraulic ram? How precisely would these strips be welded if not by pressure? Surely you're not suggesting heliarc in 1863. As for "negative" draft, if you had been around patternmaking or toolmaking for any molding or casting trade, you'd know that there is just draft (taper). Never heard the word negative used in the several years I spent around tooling for hand-laid fiberglass and vacuum-formed plastics. The only context I can think for the concept of positive and negative is in the relationship of plug to tool to final product.

jack