Of all brushes I've used, I've found that Kafka script liners provide the best size, amount of spring, and durability for working with enamels. They are my go-to brushes for tree branches, as well as thin lines of many types.
Included in this set are 6 script liner brushes, in sizes 4, 2, 1, 0, 00, and 00000. This is the set I use in all of my landscape work.
For a smaller purchase, I also sell a set of two (sizes 2 and 00000) which are the ones I use most often.