I own one of Ron Ronson's videos (the only instructional video for the moment) , the one on painting skies and I aboslutely love it! My friend in London, whom I asked to purchase the video for me in one of the book stores, also bought a little book by him "Skies in watercolor. Everything you need to get started" which is also very helpful. For the exercises in that book he uses No. 2 rigger; 25 mm. flat, hake and squirrel hair brush.
As for the paper, his preference is 300 gsm (140 lb) paper that has a meduim tooth. Ronson restricts his palette to eight colors:
Raw Sienna, Payne's Gray, French Ultramarine, Lemon Yellow, Burnt Umber, Light Red, Crimson Alizarin, and a cool blue, such as Prussian Blue. He uses Daler-Rowney's Artists' Quality paint.
I would love to get other instructional videos by R.Ronson and my already ordered them to my friend.
Hope this helps. Good luck!