For the black sex links that lay the largest eggs and probably the most the only way to really know is to buy 25 Barred Rock pullets and then put a NH rooster with 10 and a RIR rooster with 10 and wait and watch. I got my RIR's pullets from MMcMurry. Rate of lay has been very good from original stock and the ones we hatched from them are laying large eggs very soon after the first pullet eggs. A little research should be done on the source of the Barred Rock hens. Your project is not one that can pulled off the shelf ready to run with.