In the case of 50%, 66% denominations only apply tot recessive genes, YB is co-dominant the super form being an ivory.
Offsprings are either YB or there are not, there is no guessing it's visual.
In your case
YB X Bee would yield the following =
12.5% Normal
12.5% Pastel
12.5% Yellow Belly
12.5% Spider
12.5% Spider Yellow Belly
12.5% Pastel Yellow Belly
12.5% Bumble Bee
12.5% Bumble Belly
Those odds are per eggs.