Hmm. I'm sure not playing the ET game, but I don't know that I'd have stuck 'high-dollar' embryos in a recip that's got a track record of not doing a very good job raising a quality calf.
Taurus makes a decent point, and I don't necessarily cull a 1st-calf heifer if her calf doesn't stack up against those from older cows - on average, a 1st-calf heifer's calf will be 60-70 lbs lighter at weaning than those out of 4-5 yr olds, of the same breeding. So...in all likelihood, performance will be better and you won't need a nurse cow.
But, I still think that if I were going to all the expense of buying embryos, setting up recips, and implanting them, I wouldn't be putting 'em in the bottom end producers of my herd.