Did you use the code that was listed at the link I posted to determine the request size? Solving this when it's just over the 64MB hard limit will likely be very different than if the request is way over the limit. As a test for at least a more immediate workaround, what about copying an existing subscription and modifying it to fit your need for one of the new subscriptions? Perhaps you could also take a look at the rows in the report server database to se if the requests are significantly different between the new and old. I would not be surprised to se the new requests somehow adding overhead that could likely be removed by changing some report server options.