CSP? I've never heard of it. I'll give it a try, thanks. :DClip Studio Paint is very good, it also has 3D models for you to use if you're having trouble with certain poses. CSP is like a mashup of Paint Tool SAI and Photoshop, but much more oriented towards drawing compared to Photoshop.
Sometimes there will be a sale for CSP where you can get it for $15, which I think is a good deal!