I recommend not using color preservative at all. my reason for saying this is that CP will fade with time. A better alternative is to use NCP(no color preserver needed) thread.
The NCP thread will retain its color.

I might also mention that if you plan to build more than one rod that you make a color wand. This is basically a piece of broken rod with all the colored thread you may wish to use wraped on it. Each color is duplicated. On one no preserver, on the other use preserver. If u want you can add a wrap of NCP also. when finished coat them all with epoxy. You will be suprised how many different shaded you wind up with using just one color.It is very beneficial to know what your wraps will look like before you start. It's a shame to apply all the work in color selection , wrapping, and finishing , only to be dissapointed with the end result.