me years ago, is that when he goes to the warble over the V chord, the
interval is a major third - he's playing a 4-5 draw warble in first
position. If you play it in cross harp, it will be a minor third. Listen
carefully when Muddy sings the line "I'm your Hoochie Coochie Man..." - the
warble in the background is a major third - it won't sound right on a D
harp.
I hope this helps - I know it helped me. This was the tune that opened the door for me to do a bit more sophisticated 1st position playing. Once you get this one down, you'll start to hear first position all over the place that you previously thought was cross harp.