dr del, you could do the same thing though. Call or email all the ball python breeders that mention breeding spiders, and ask if they bred spider to spider, and what was the results.
I'm sure most wouldn't mind giving you the information. It would be a cool little study to work up. Given the number of hobby breeders with at least one spider to breed, it could be a great deal of information.
I know! You should get a government grant for the study! LOL.