I really doubt you could ever make $750,000 bulls with 4 cows.. Look at the big operations, 100's of head and they've been doing it for decades, and it's still a small percentage of the bulls that get the big money, and part of the reason they do is they come from large herds that have registered and tested offspring, siblings, dams, sires, aunties and uncles and cousins for so long.
Try it, get an ET calf from SAV America and the most expensive dam and go try to market it.. even though you have the same genetics you won't get a tenth of the price had it been born on the Schaff ranch.