I'll post another vid soon where I use mypaint for most of the grayscale preliminary work. Mypaint is the best it has ever been since I first started using it. Things have been added to it that have been down right awesome. I can't even complain a little about the program too much anymore, but a few things are still not there that prevent me from doing a digital painting from start to finish. For example; I've become accustomed to using the selection tools to isolate and contain certain sections of the painting for effect (like the mountains in the dragon painting), also I heavily use the transformation options in Photoshop to enlarge, reduce, and rotate certain parts of the image, layer masks to keep things tidy while I paint, and lastly the crop tool to fix the size of the canvas if needed. There also the issue that Mypaint doesn't fully support an overlay or colorize layer officially yet, although I am using a colorize layer build that Andrew Chadwick made in branch - things still could be tweaked.
If, and when, someone adds selections tools, transformation tools, and a proper overlay or colorize layer options, the hybrid method for me will work best. I still love, love, love, Mypaint for what it does do right now though. It's still super slick to used and still isn't over burdened with nonsense features yet has so many cool features in it, and that is what makes it really fun to use.