I would post about this on the polish site for the best advice.
I can try to help you through this if you cant find any better information. but im far from an expert in polish breeding - I just got my first polish this year.
with old English, I am more familiar with the colors, if you breed self blue to any color offspring will normally be the other color. I found this out when I tried to breed wheaten to self blue. ive also used the self blue to even the color in blacks.
if it were me, I would breed several pure bred reds. taking the best rooster over larger more dominate hens. then select my best rooster from that mating to use with the red blue crosses you just made.
just for fun I would also reverse breed, some blue hens under your best red rooster. from this mating I would select the ones marked like your black/chocolate.
the only way I know of breeding pure chocolate is with the dun gene. I have it in my old English stock to breed fawn/chocolate. im pretty sure it also exists in orpingtons and wyandottes.
I hope this helps.
brian