I am using the standard glass less carriers made for LPL 6700 like here:
Also, here is a picture of the head on LPL 6700 (not mine, shamelessly copied from Google image search):
I am not cropping the image. The projected image is exactly what I see from the 6x4.5 or 6x6 negative. The stray lines of light are beyond the projected image on baseboard alone (no easel). The lines stay there no matter what aperture I choose on the lens.