I pulled the masks out, used aquarium tubing to protect the film where the mask used to, then used black bookmakers tape to blackout the inside. I used the bookmakers tape to make a flap to protect/shade the red window outside. I also added some weather strip foam in the roll compartments to keep the film snug.
These mods seem to have solved the stray light issues.
The other thing I did was to tape the bulb switch in the normal position, it sucks to run around shooting oblivious to the fact that you are in bulb.