CDs, and I suppose I could do without alternates, but I'd be interested to know where that is available as well. From what I can tell, RCA only did various greatest hits releases of this material, and not any multi-disc sets other than the Blanton Webster set. Originally I thought I would try to minimize duplication by not getting the big RCA box, because I probably have about half of it, but getting all the Chronological discs would likely end up costing more anyway, and I'd have plenty of duplication there as well.
Edit: I guess I was mostly surprised at how much material on RCA Victor there is from that era. I knew there was a decent amount that I didn't have, but 6 whole CDs worth was surprising. I figure there has to be a lot of great stuff there.