Ask how many greyhounds they have in their practice. Also, the college the vet graduated from may tell you how familar he/she is with greys.
A vet not familar with greyhounds can cost you a ton of money. EKGs, blood work, etc because they are not used to listening to greyhound hearts, not familar with greyhound blood values, etc. I had one vet tell me SieSie was in congestive heart failure and she was fine. I've had vets look at blood work and think the dog is fine when in fact there is a problem.
If you have a vet willing to work with you and learn, it's worth training him/her. I have one that is great with greys and quite experienced treating them, and I still took the article on hulling corns to him. He read it and did Mahogany's corns