Here's another drill for your ring/pinky independence.
In the first bar we have the full lick. I recommend that you begin with strict alternate picking, starting with a downstroke. In bar two we repeat the first two beats of the measure so we can begin to isolate and identify any difficulties that we might have in our technique. I noticed that the "inside picking" (shown in bar three) needed some extra work when I played bar two, so I made an exercise of just two notes. After working on bar three, go back to bar two, then try the first bar again. You should see considerable improvement!
Try applying this isolation technique to anything that you find challenging; I think you will find it very useful.
