Hi Jamie,
Firstly, thank you for your generous, if not oblique, compliment. My back feels suitably patted. I only hope Mr Lee will accept my apology and forgive me for questioning the accuracy of his painting. I sent him a PM but have not had a reply so far.
Secondly, the tricorn hat was shaded and highlighted using Black & Black/ Grey acrylic paint and finished with a dusting of black pastel.
The texture was actually created by dusting the hat in talcum powder while the base coat was stil drying and then spraying dull coat to seal it to the surface. The talc creates a very fine, smooth and even texture, which can then be very lightly dry brushed. It creates an effect similar to the rough texture of wool, which looks quite realistic in this scale.
This is an old trick taught to me by Phil Walden 20 years ago, and I still use it when I want to replicate rough textures on uniforms and hats etc.