Check this thread for Blu-ray versions of despecialized.
http://originaltrilogy.com/topic/Star-Wars-Despecialized-Editions-Custom-Bluray-Set/id/49995
Yep. Those are the way to go.
But you can also just use your MKVs and tsmuxerGUI to get it into a blu-ray ISO. In fact, that’s exactly how we would’ve answered the question a few months ago, before those great new discs. 😃