Watch the Major Third online guitar lesson by Kai Eckhardt from Atomic Bass: Reactive Intervals
Playing this variation will be fairly difficult if you don't have a good grip on the previous exercise. However, it does not matter how slow you play it as long as the timing is even and the notes are nicely connected to one another. By shedding this variation you will get a really good sense of measure across the neck. You are on the right track when a large step like a major third visually looks to you like a single unit. Then you are ready to transpose the idea into all three tonal centers presented: A, A# and B.