For this window, I chose the most popular width of copper foil, 7/32". There are six widths from which to choose, but this size works for almost all projects. The foil comes in a roll as pictured below and is self-adhesive. Just peel back the paper backing in small lengths .. it tangles easily.
Foiling is completed one piece of glass at a time. As each piece is removed from the pattern and foiled, it gets replaced back in. The fit of the pieces is important .. Not too tight and not too loose. At several points during this process, I brought individual pieces back to the grinder to give them a little more "breathing room."
Thanksgiving is almost upon us! I will be back soon to show the window soldered.