I use thin cardboard (cereal box) to make the new film guides in the back. Just glue them over the old ones. I use the original lenses. On one I modified the shutter to get 1/50 second speed. The other I left at the base 1/30 second. The round photos were done with a mask added in the back.
A 116 box camera will give 6 -6X11 photos on 120. I moved the red window to the center of the back and used the middle row of numbers. You only use the odd numbers, 1, 3, 5, 7, 9,11.
I have the pics of the mods on my blog, and I will be posting a Kodak 3 modified camera today.