I'm working on learning this and want to make sure I'm doing this the best way.What is the best fingering for the left hand here?Is it5 3 2 1 4 3 2 1 2 3 4 1 4 1 2 3 2 3 ?I'm not sure if it's that way because it's a little awkward going from 1 to 4 the first time.And do you do it thumb under or not?