What i noticed from a wc pbb is the head shape, more square and pretty bulky with small eyes, like i said earlier i havent seen a big cb pbb so i dont have something to compare it with.
Just a ex. Of a nice WC koliba vs. CB koliba. A WC koliba will have a pointier snout, And flat head vs. a cb koliba which most have round snout and fatter head.
Another ex. A Wc nigerian lap vs. a cb lap. Wc nigerian lap will have bulky head, flat head and square snout vs. a cb lap which will have the same as the cb koliba.
Im not sayin that the cb pbb will have this characteristics but it might if its a cross breed with a lap, we dont have the source where it came from. Like i said i might be wrong, im new to this cb pbb.