Hi Tony,

I use TransTint Dyes  with alcohol. Then it is a matter of getting the saturation up. That usually requires a few extra drops of dye in the solution. Extra coats can help but sometimes the new coat wipes off some of the previous ones. Yellow needs the richest concentration.

I've got a gray one I'll post in the future that was done with reducing the black dye and testing  until I liked the result.