I have been working on puttying the panel and just completed the back side. This is a traditional process in using either lead came, zinc came, or other type of came that the glass fits into. There is a space that the putty/cement fills in that used to be for weather proofing a stained glass panel as well as making the panel more secure, stronger.
I will be cleaning up the excess and let it set for a couple of weeks as it dries. While that is setting up I will be beveling all the color pieces that will eventually be bonded on top of the clear bevels.