OK without rim (24 x 18 x 16)?

piano wire the very small stuff or heavy fishing line. You can heat it a bit with hair dryer and that will make it cut a bit easer. be carfull to not break the panes of glass they crack easy do not use anything metal to get your saw started ( fishing line) just start at the top and go down. the bottom should be the easy part I have found that they leave a bit more room down there and just silicone it more you should be able to use a raser blade there.

Bill