Lightnin’ recorded this song lot of times however his finest version is the one he taped for the Seattle Folk Society in the late 60ies. He remained in extraordinary type, here’s his variation https://www.youtube.com/watch?v=zkYFfVJuGvo
You’ll see that the type he’s playing is longer that the typical 12-bar blues. He does this regularly so it’s not an “accident”. I believe the factor is that he desires to do that cool upstroke twice, and you can only do that if you prolong the progression. I followed that too so “blues authorities” … get lost;–RRB- I likewise added a solo from another variation.
Standard tuning, secret of E.
I’m playing a 1925 Gibson L3.
More Lightnin’ stuff at.