Brian, is there a reason why you want the smallest baby brine shrimp for your black rams? I've not bred blacks but when I bred German Blue Rams and Gold Rams regular GsL brine shrimp cysts were fine for fry. Are the blacks a smaller ram?
One area that really seems to be when the smaller San Frans ones are helpful is when artificially breeding Discus.. the discus fry will take these easier than the standard GSL ones. Ive never used them as they are more expensive.