Hi there. I've been doing stained glass for many years. Yes, you can make a window this size using copper foil. I would suggest that you choose a wider foil. I have made some very large foil windows and have soldered copper wire, which bends and twists nicely, following the vertical lines of your pattern as reinforcement. If you are still hesitant, you can divide your pattern into 2 or even 4 and use perhaps an H zinc channel and design your pattern to carry through from one section to the next. It is not uncommon to combine both foil and H channels. Hope this helps and p-ost a picture when you're done!

Dear atouchofglass,

Your encouragement is appreciated. I have been using 1/4 inch foil which gives me thicker solder lines, and for me, is easier to handle. Also, the copper wire reinforcement is a great idea. And thanks again for responding. After posting many weeks ago I didn't think any information would appear before I finished the project. But, alas, with my busy schedule the window project is still very much in process and you input is very timely. I will get a picture uploaded when finished.

Can't wait to see it!