I'm trying to sort out my thrum position playing for jazz. It's been ok for basic classical stuff venturing up and down a string but I find when solo-ing its really not great for crossing strings. I'm trying to play a lick (actually it's the opening lick from the piano solo in Freddie Freeloader that moves across the D and the G string. Should my thumb be fretting both strings (this seems to hurt A LOT) or jumping string to string? It's a fairly fast lick but seems really tricky to play on the upright either way and I'm really struggling. I've attached the lick (playing it up the 8ve from this transcription) Any thoughts well appreciated.