@megalosaurus I find you can get a bristle brush with plenty of variation if the tip dots are of varied densities and sizes and spread unevenly across thetip shape AND the Brush tip "Direction" setting is set to " direction of pen" ... again by clicking the little icon to the right of the Direction setting.( wise to also slightly blur the dots and set the gap setting to a small gap). However for a brushed look I rarely use bristle brushes digitally ( in any program). While the brush can give a stroke that looks like a bristle brush its effect gets lost in a complete painting. I find you get better results, more control and faster workflow by first painting with simple brushes, fills and gradients and then using a bristle style BLENDER at the end. I also created a thick paint simulating brush ( Van Gough style)... which is applied in overlay mode again at the end.
Or for an instant solution I may use one of my 60 artistic filter Actions....e.g. I have ones that divide the image into zones and then "brushes" the zones in different directions