A Google search for "isonomia David Sedley" revealed the book Creationism and Its Critics in Antiquity by David Sedley. It has what appears to be a pertinent chapter titled "Epicurean Infinity". https://books.google.com/books?id=SgRuJ…epage&q&f=false
It's always worth asking David Sedley
Thanks again to Godfrey for bringing this book to my attention. Its focus is much wider than Epicurus alone but it has excellent material on the Epicurean viewpoint. I am not going through it for the first time and so I am setting up this thread for future comments.