There is no such thing as a het. Yellow Belly. Yellow Belly is also referred to as het. Ivory.
If you breed a het. Albino to a het. Clown each egg has a 50% possibility of being 100% het. for Albino and Clown.
That breeding would be a total waste of time. If you breed a YB to a het. Albino each you would (theoretically) get:
1/2 normal 50% possible het. Albino
1/2 YB 50% het. Albino
Also a waste of time in a my opinion. I would be me an Albino male if i were you.
Regards,
Bas