Thank you, Visitor, for confirming that the 2 piano edition is in fact the rehearsal score (and, as one would expect, contains the "original solo piano part" and an "orchestra piano part"). I appreciate hearing from someone who has performed the work!
Thank you also for the link to Hal Leonard's page. It is apparently also available
here (though I'd probably opt for purchasing through HL, that site gives a 1 page preview at least).
I was personally hoping to have a chance to try it out before purchasing--to see if it was even realistic for me to play it. In that regard, it is available in
PDF from Scribd (albeit only for members who have uploaded). If, for some reason, that link is not allowed here or no longer works, please feel free to message me.
Thanks to Quantum also for the suggestion about an interlibrary loan--I may need to do that for the score. I was hoping to avoid rental costs, but given the works' status, I suppose that might not be possible. Amusingly, I think by the time I'm ready to play this piece, it may well be out of copyright!
Thank you again for your assistance. I hope to have a chance to play this wonderfully melodramatic piece.