Way off topic from intial thread reason but never mind. Maybe this info is useful to some people here. Don't bother with these crap commercial apps. There is no point anymore.
I've spent months going through all these painting apps. Now I'm implementing almost everything they do in Gimp and Mypaint by building brushes etc that do generally the same thing. SAI is dead because I've looked at how it's brushes achieve the efficient results and I've created the same thing in Gimp except for the fact that Gimp can only mix paint by using primary and secondary colours. It works. It's not actually crucial to have canvas mixing to be honest. Photoshop users dealt with this until very recently and created great work. Mypaint can do it anyway. I'm also creating various textures to use as alphas for paper etc.
I've got hundreds of brushes for Gimp and Mypaint now.
Corel are having a laugh. £274.80 download costs for a broken application.
I'll have to get a website soon for all this material. I could fill an entire website with the findings I now have to basiclly do away with these commercial app painting jokes. I've had a cool domain name for the last ten years that hasn't been used.
Here's some experiments in Mypaint utilizing various textures and alpha techniques: