For Fans of Bruno Walter's "Indian Summer"

I'm very familiar now with Columbia pressings of Walter's late (last) period of recordings--whether on 6 eye, 2 eye, Odyssey or Columbia Masterworks Portrait but stumbled upon a Japanese Toshiba pressing of his Mahler "Das Lied" in a series of releases called "New Remix Masters" under the aegis of Sony/CBS. Very impressed. I don't know what they did, I don't know if they're digitally- remastered or not, but they beat the pants off the originals in every way. Much blacker backrounds, more air around instruments, a sense of hall space, better dynamics, better burnished brass...amazing. I've since picked up the Walter Mahler 1st and Brahms' 3rd. The "boogie factor" is retained, unlike the King Analog reissues, heck like most re-issues.
Where can one find these for purchase?

They show up on Ebay occasionally as "Japanese-pressing" at least and hopefully advertised as "New-remixed masters." Other key words would be Sony/CBS. The Lp's all have a grey border and black triangular fill in the lower right corner, where the logo appears in metallic gold. The cat numbers for Walter's Mahler 1st is 20AC 1830. They did all his Brahms, some Beethoven and some Mahler, maybe all of it.
I'd like to hear his Beethoven 6th and 7th... have you tried those yet?
No, I've only seen the 9th on Ebay occasionally. Someone on here must know the whole story....
VERY interesting. Would love to hear one of these pressings.
I'm in the Northern California area if you're driving through!