Winsor & Newton Cotman 111 Round Brushes are all great brushes if you are looking to do lettering with watercolour. The brush is soft, smooth and flexible. It can give you beautiful thin strokes and details as well as thick downstrokes.
From all brushes I have tried, this is my favourite.
I would suggest getting the sizes No. 2 and 3. If you are new to lettering with watercolour and paintbrushes you should probably start with No. 3.
Artwork created with the Cotman 111 Round
Here’s a few examples of some of the lettering I created with Winsor & Newton‘s Cotman 111 Round.