This month's DPG using Brushes with David Hockney's advice: thumbs only
This was done on my iPhone using the Brushes app and is my submission for this month's Deadline Painting Group. The theme for DPG was "Face in a crowd." I read that David Hockney only uses his thumbs when painting with Brushes, as you actually have greater control than if you use you finger (and consequently, your entire arm and elbow). My experience in using the thumb-only was a bit messy, but also gave me more freedom of movement. Will keep using this practice with future Brushes paintings.