How to tint kyan’s works paste for darker skin tones?

i am new to blythe and doll making in general so i really need advice on how to get my kyan’s works paste to match a darker shade!

as far as i’m aware some doll customizers use pastels to shade match but my arms might be growing out my nether regions cause no matter how hard i try and no matter what proportions i use the paste seems to be soft and crumbly like a damn cookie after baking it in the uv lamp. haven’t had this problem when i wasn’t trying to mix in the pastels!

could it be that it’s the paste reacting to this specific brand of pastels or are there other more fool proof methods of tinting the paste? before anyone suggests just buying a pre tinted paste i am (unfortunately) unable to use ebay because i am not american or anything adjacent 💔