Let me ask a question here. You want to breed your own birds? For yourself I hope. You shouldn't ever sell or give away any birds that had Marek's. Your flock may become immune or I should say better able to fight off the particular strain or strains they've been exposed to, but that doesn't mean they are safe for someone else.
Last season I purchased over 100 chicks. I lost 85 of them last summer and still counting. Quite a few of the breeds purchased were all wiped out in a matter of weeks. Some have lingered but unfortunately don't have any long term survival chances. I really think you need to think very hard on what your expectations are for the long run.
I will be breeding them for myself, and hatching eggs... I am pretty sure the eggs don't carry the virus. And I know it is risky to get non vaccinated birds, but this man's birds are very strong.SO I will try, and get the strongest chicks possible, and hope for the best.