If you look through my websites and other posts I talk about working in the traditional method of stained glass. I use lead came and not the copper foil. How traditional is it? And how much has it changed? Well one way is to look at the tools we use today and compare it to what was used over 250 years ago. Above is an illustration from Diderot's Encyclopedie of 1751-72 showing some of the tools used to make leaded glass windows. You can see a glass cutting tool, pliers, hammer, etc.
Here are some of the tools I use to make a leaded glass panel. No real big differences. Making a leaded glass panel means using hand tools. The techniques and tools have not changed much.