I've been admiring Ben Fenske's work for a while and had the opportunity to see him do a demo yesterday. He painted from a live model with about 25 people in attendance at a studio in Waltham, MA.
Ben sat while he painted and started off with a special paintbrush- two paintbrushes taped together to make a longer handle so he could get a little more distance between himself and the canvas. I'm going to try that! He used Utrecht bristle brushes, mostly sizes 4, 5, and 6, long filberts and flats. Unlike me, he doesn't keep a container of mineral spirits to swish his brushes around in. Instead, he holds 8-10 brushes and uses a different brush for each color. All he had was a little container for his medium, which was linseed oil and turp.
He painted on Claessen's pre-primed linen. He had washed some color onto the surface of the canvas before he started. His favorite surface, he said, is an old painting, because he likes the unexpected colors and texture that he gets that way. He doesn't do that for demos because it would be too difficult for people watching to see what he's painting. He spent a lot of time trying to get an accurate drawing to start with, carefully measuring and comparing.