I modified the Bambu Lab spool holder rescue by bounetphoto - MakerWorld to facilitate double stacked reels so I could keep my favorite colors at hand to feed into the 4 way splitter. This is the stand only (2 shown). I also developed a simple marker cap (in green) that can easily be moved to show which spool is currently in use as this is not easily visible in the 4 way splitter.

Enjoy