I"m not sure about the scale on my "leading"

nice! I was trying to think of different ways to make lead inserts or leaded windows.

How about draftmens tape. I think that's what its call. It's a thin tape that they use to out line blueprints or they did before cumputer drafting. It use too come in many colors and 1mm and up.

Leading comes in various widths. For an old window of this type, the wider leading is not out of character. (Back in the day, I owned and operated a stained glass shop.)

You can also use a lead tape that golfers use to adjust the weight of club heads. It cuts easily with scissors or a very sharp eXacto knife.

This is gorgeous! Nice job.