Well, Jamie, I shot a couple rolls through my two original Panorams and both had terrible flare comming in from the sides of the negative and bleeding toward the center. On some of the prints as much as 1/3 of the print was completely washed out.
That's why I thought a foam or velvet "donut" around the window on the inside of the back would keep the light from scattering around the inside of the camera. I don't think it would be a problem if any light entering through the window was kept solely on the film backing paper by the "donut". I'm going to try it on one of my No. 2 Brownies (which also has a light leak at the red window) to see if that donut will cure the problem.