I use Jason's standard purple colorant right now until its gone then I'll switch to the X2. Here's the purple I mix up for all of my standard purple colors.
1/2 cup plastic...Jason's Phthalate- free or "green" plastic in soft
12 drops of stabilizer [ this gets re-heated a bunch so you may not need this]
70 drops of purple
equal parts of Jason's light purple and blue glitter to taste
violet hi lites to taste, a match-head size dip for mine
This creates a really electric purple that is still very transparent. I do all panfish plastics and I like super strong yet transparent colors and I like the colors to have an "internal" character to them, hence the hi lites and two glitter colors. A small amount of bright red glitter might do something to this formula for you too. I have fished this color right along side of other purples and this one sets crappies on fire by comparison and I am convinced it has to do with that "internal character" I mention created with the additives and very transparent color.
As with all colors, personal preference to color strength and the additives varies widely so I think it would be wise to start with fairly strong color and add the extras a bit at a time and if the original color is too strong just add in raw plastic to suit your needs. I find it easier to thin an original color if it is too baudy for me rather than to try and add more colorant to strengthen a color. That might just be me.