It's a bit like the fourth bar, where thumb and index finger have to play the same string."
You're right.
Bar 4 gave me - and still gives me, but for other reasons - quite a hard time. It took me quite a while to understand that I could play the 4th string (2nd fret) with my thumb instead of the index, before plucking the 1st string on the 3rd fret. (Is that clear !?)
Finger gymnastics !
Going to bed now...
Thanks for your tips.