What do you want to do to the clear dope?  Transparent or solid ?

I tried India inks, don't, mine I think were water based. Can you  say MESS?

I have taken a few drops of red, in thinner and mixed that with clear and got a nice tint...Do experiment on something other than the model..

I use a lot of aniline dye for tinting in the guitar shop, and have tinted nitrocellulose lacquer and K2 clear as well.
They are readily available but pricey

You can buy candy and pearl powders on line  to tint clear dope...i bought some pearl violet powder and put in clear the sprayed it over a black base

yes In did the same thing Igor orange pearl, just use a white base on yellow's and red's

In my case i wanted the darkest purple i could get so i used black