Wow that trip sounds incredible, seeing a master work with coal like that. I actually switched FROM propane TO coal after a similar visit to an old workshop in Scotland, and man the difference in how the metal moves is REAL. That softer heat he talked about lets you feel the steel bending almost before it happens, which changed my scroll work completely. It's a filthy messy pain sometimes but for detailed stuff I'm now convinced coal gives better long term results.

Maybe inspections only check for obvious problems.