Don't expect too much from the x-ray. It will be exciting to see definite pups, however, the vet's sentence will probably end with "....or there could be more). That doesn't help a bit. I've had a vet SHOW me 5 definites and we had 4. Same thing happened to another member on here at the same time. Sometimes they say one is too big when, infact, there isn't one too big. However, for some reason, you will find comfort in seeing an x-ray. I don't get x-rays anymore unless I FEEL something may be wrong. Can't wait 'til tomorrow to see what shows up.
Now what the x-ray can tell you is if the pups are lined up and ready to go. HOWEVER (don't hate me), mine were all lined up, she didn't have the pups, took her back 48 hours later...another x-ray....pups were out of position. I'm just trying to help, believe it or not (smile).