Here's a couple of faux windows I just completed. The fall one is listed in my Etsy shop. I love the addition of burlap to the love frame. It really helps the words to standout.
For the "glass" I used Better Than Acrylic. You can read more about the original BTA HERE. For my faux glass windows... I used a heavier grade than the original that I use when cutting it on a die cutting machine. I am contemplating offering the heavier grade BTA for your window and frame needs. You can use the original, but I've found if the frame is on the larger side, the original flexes a bit too much. The heavier is more solid like glass. I love that it is So Crystal Clear, it won't crack or break and it's so easy to work with! It does Wonderful with vinyl which makes me Happy! :)
If this is a product you might be interested in... please leave me a comment and let me know. :)