Your film is so spectacularly insensitive, that the UV attenuation from your red filter doesn't change much. If you can get the process sufficiently reproducible, you should see a slight difference in film sensitivity with and without red filter.

BTW: you may be able to get better results if you add KBr to your CuCl2 bleach. We all know from Microdol that Chloride is a weak Silver solvent, whereas if you add Bromide this effect should be mostly suppressed.