Wish to upgrade phono preamp caps and other

Looking at my PS Audio GCPH I see 4 12000uf NCD caps sitting in what I believe to be the signal chain.

I wish to upgrade to best possible caps in that location.

I'm finding it difficult to locate any 12000uf caps let alone some really good ones that will fit in about a 35mm wide X 45mm high location.

I understood there are companies that replace these caps with Muse but Muse doesn't make that value cap.

I'm not electronic savvy but shouldn't you replace with same value cap?
I doubt that these Caps are in the Signal Path . They are more than likely in the Power Supply and are Electrolytic .