It would be nice if players have an option to use any color defined by an hexadecimal or RGB representation for a color to multiply the possibilities and make the sharestone more "scalable" for servers with a lot of users using it. Servers admin would be able to deactivate that feature.

For retro-compatibility, dye colors would be transform to their respective RGB/Hexadecimal representatio. The choice of using hexadecimal, RBG or any other representation of colors would be up to the person who add that with technical limits and complexity

The plan for the future is actually to move away from colors and use other designators as a more accessible solution. Allowing arbitrary colors would be very unintuitive since there's no visible difference between many of those 16 million colors. It would really become more of a "password-protection" at that point.

However, if an addon mod wants to add fine-grained channel-scoping of waystones or sharestones, I'll be happy to extend the API as necessary.