I got the semen from Heartbrand. I used the same bulls in Y1 and Y2, but mixed it up in Y3. Haven't got to Y3 calves yet to see if there is any difference between the lines. I think the Akaushi offers more for the commercial cattleman than the black wagyu. If push comes to shove, I feel confident that I could slide the F1's into any load at a sale barn and they'd never pick them out...or atleast, from our small sample size, you couldn't tell much difference in the F1's and our Angus. The F1's from the Simangus cows were thicker than the straight angus'. Both were good, but from a phenotype standpoint, the SimangusXAkaushi F1's were hands down the best.
In regards to CE, the bull we used in Y1 and Y2 threw calves from 55-125#. I truly believe the Ak CE will match the cow. If she throws small calves, I think the AK offspring will be small. If she throws giants, it's Katie bar the door! I've noticed they are a bit longer on gestation, but we are talking 3-7d on average. The 125# was 18d late, maybe more, can't remember right off. Had parentage to confirm AKx. Given, the cow he was out of always throws 100# calves, he just happened to be the biggest she'd ever had. She calved that thing 100% unassisted and when I found it, the little stinker was already bigger than his herdmates and tame as a puppy dog his whole life. (Hung a 859# carcass at 22 mos..Was ready earlier, but had to wait until I could get a spot at the processor. he was off feed for ~55-60d prior to harvest.)
I'd like to try a black Wagyu for myself, but I've not found a way to make it pencil out for me. I direct market, but pretty sure I could not get the premium warranted to take an animal another 300+d on feed. I'll stick with the F1's, they'll get there quicker and hang a carcass that's "Good enough for me!".