There is a picture of my current Global Pressure Mapping settings. I do not know but these works for me.. and mine N900 device, these could be little different for every device. Setting up global pressure is bit a tricky.. experiment, please. Maybe I try to do some instructions.. how I have customised mine brushes settings and how I can done different like textures and dynamic effects with MyPaint brush engine. Let's see... at least I could throw some example pictures.
cat .mypaint/settings.conf