Since iridescent finishes were being widely used in Bohemia, France, England and the US by the end of the 19th C (see Revi's Nineteenth Century Glass, Its Genesis and Development) it seems like it might be more productive to look for the shape or other clues as to manufacturer (easier said than done!!!
). Sorry I can't be more help; I looked but couldn't find anything that matched.
Just an aside: I noticed yesterday when looking at the site Andy provided a link to that Villanueva-Colado mentions some pieces in the Hosch section of Truitts' book 1 aren't actually Hosch. He surmises that "FROM THE EVIDENCE, IT SEEMS HOSCH WAS A DECORATOR OF BLANKS FROM OTHER FACTORIES." Appears he didn't read the text about Hosch in the Truitt book, which states that not only did they refine glass made by other companies, they were an exporter and purchased hot decorated and already-refined glass as well. Ach, it's all so complicated!