There is an idea called the 10,000 hour rule that basically is that in order for you to be really good at a task it takes 10,000 hours of experience....that would apply to embryologists...If you have an experienced person he or she won't implant if everything doesn't feel right in the recip. Sometimes they will use ultrasound to verify the recip is ready. Depending on the breed of your embryo I would say that those embryos should be out of outstanding, way above average cows considering the price you gave. In other words, what price would the calf be at a sale if you were selling it? If you are paying $400 or $500 for an embryo you need to be getting more than $1,800 or $2,000. I personally don't trust some of the prices I see on some of these online sales...especially when you constantly see embryos out of the same flush auction after auction. Some breeders even sell embryos without showing you a photo of the actual donor. Your recips need to be in really good body condition, use multimin, good minerals and use either heifers or cows who have weaned their calves to improve your conception rate. Good luck.