In his Illustrated Postage Stamp History of Western Ukrainian Republic 1918 - 1919 (1973), John Bulat shows this Proof sheet of the overprint setting for the Fourth Stanyslaviv Issue, second set on high value Austrian Postage Dues (pp 83 - 84). In his later Catalogue, these overprints become the Eighth Stanyslaviv set (Bulat 104-105; pages 168-69).
The Proof sheet passed from Bulat to Ron Zelonka and was offered in the Corinphila sale of his collection, but was only sold after the Auction. It is now in my stock.
As far as I know, it is the only Proof sheet of any of the West Ukraine overprints. If I am wrong I would be pleased for someone to tell me!