So, the good news is that I now have the Night Shade Books edition of THE GHOST PIRATES, which brings me up to four out of the five-book set of Hodgson's complete fiction.
The bad news is that it's the sole missing volume I really need, the one containing his masterpiece,
THE NIGHT LAND. Unfortunately the small press that released this set seem to have seriously underprinted the third (GHOST PIRATES) and fourth (NIGHT LAND) volumes in the series, so that these are disproportionately expensive, whether in hardcover or paperback.
On the other hand, in related work I've now been able to establish definitely that Lovecraft and Smith discovered the work of Hodgson in 1934. So I was wrong, back in my 'Classics of Fantasy' column on THE NIGHT LAND when I said that Hodgson's work was a direct influence on Clark Ashton Smith: Smith had already begun his Zothique endtimes series in 1931. It seems to have been convergent evolution, not influence either way. Good to know.
--current reading: Brian Aldiss's BILLION YEAR SPREE