How to keep gradients consistent in animation

I’m in the process of deciding what style I would like to employ in my current animation process but I realized I am avoidant of any character designs that include gradients. I usually go for anime style frame by frame so I need to be able to keep things consistent with every generation of gradient.

Whether it’d be a soft gradient within the eyes or a the blush of a cheek, how can I approach these areas so that the parameters can be accurately controlled across multiple hand drawn frames?