I have the same mind set as Frax re Rubber Rings.
If I can't do a complete game with the same color Rubber Rings I don't really see the point in making RR's, with this caveat - unless I WANT to mix & match RR's dependent on the PF colors. But that will still necessitate making RR's in ALL the standard RR sizes in at least a few colors.
I had the same issues with Gene's colored RR's he didn't have what I needed for most Games to be all 1 color so I didn't buy any.
Maybe concentrate on a smaller set of colors in ALL the standard RR sizes & add colors as sales & specific color requests support them?
Pin - K
www.KimballsPinballs.com