I can do all three, or in my case five if one throws in silver fillets and gas welding. But my main entry was from outside frame building so I am not really in any of the camps. I own, for instance, a Rockwell tester. I think if a lot of framebuilders who are serious on issues like heat and impacts on metal did any testing they would be reasured.
I don't fully know how lugs were made pre casting, and I am OK on casting. I believe the method involved forming them out of sheet metal, but I could be wrong. (did a little check and on Dave Moulton's site he says they were sand cast; then when materails improved they were stamped out of sheet metal; And now investment cast.