Shito Rhus microphylla

[GreenGnome]

This Rhus microphylla is 4 years old and 9cm tall. I just put it into its first bonsai pot(I think its too big but it was the smallest I could find). I have not touched it yet as it seems to style itself by dieing back at the tips during its dormancy. Its got about a month before it leafs out so I figured if I am to do anything I ought to do it now. What do you think?