Hi Tony, yes I agree, this one is a bit tricky to get the hang of!

You are okay just hitting the muted D string on those boom chicks. Playing it that way actually sounds a little cleaner than the way it's played on the original recording.

Generally, speaking, I would encourage you to practice through the song at a slower tempo if you're struggling with it up to speed. Putting in lots of practice at a slower tempo with plenty of repetition is a more efficient method to get the hang of the parts and be able to play them up to speed with the track much quicker!

Let me know how it goes!

Mike