Besides the colour pallettes OT has some very nice tools when it comes to painting. I particularly find the rectangular selective fill extremely useful. Let’s say that you have painted the wolf’s face and the inner mouth and tongue, and now have to paint all the small sharp teeth. You just pick the colour a draw a rectangle around the mouth – and you’re done. And if you do it in multi mode you can do this on several cells at a time. It’s also very useful for eliminating/finding unpainted pixels, that will bloom up background colours in the render. Paint your cell with a screaming colour using this square tool after painting the cell, will make these show up.
Many animators use other packages for animating but do their final painting in OT and for good reason. I suggest that you use good time studying these! Feel free to reach out if you like!
NB: Ghibli uses this program in a particular manner. All drawing are scanned and stored in 5K resolution lineart B/W and interpolated in the render. So no grey scale but a very high resolution. It makes the painting part easier I guess, but it’s not the common workflow among users. Or any other program that I know of.
Congratulations with the 5.0 alpha will definitely give a go asap.