I simply used today a 2B pencil and watercolour. I noticed that doing a wash on this Moleskine sketchbook, the paint stays longer on the surface compared to the cold pressed  300gr Arches watercolour paper for instance.The advantage is it leaves more time to move the paint around, a bit like on a cold pressed paper. The drawback is the paint once dried is more difficult to lift… I liked the imposing hat for this portrait !