I have perused through the extensive threads on the Rachmaninov Concerto Review project. Thanks for all that hard work. I am wanting a single disc (or box) with all the piano concertos. Or maybe two discs if necessary. So I am seeking a compromise--best set altogether rather than XXX for Concerto 1, YYY for Concerto 2, ZZZ for concerto 3, etc.
I am new to Rachmaninov and confessedly by the standards of this board under-educated musically. This is what I have:

I bought it on a lark in a used bookstore. I enjoy it, but I am guessing there is something better out there.
Here are some recordings I am looking at (based in part on the Review Project).
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This last is obviously only 2 and 3, but if I am advised that this is a must have, I would be interested in this plus another recording that has the other two.
I really appreciate the advice. This is the most knowledgeable music forum (or really forum on any subject matter) that I have ever stumbled across.