Thanks a bunch for the tips, monk.
I tried it with 53-1-3-1 in 548 but then I had trouble returning to 51-2-1-2 because of thumb being occupied, and my hand got bent a bit when reaching the pinky on that black (I like to keep distance from them if I can afford it). I think I will try to get through this with 2-1-2-1 for every bar. The subject "striking chords" was referring to how I found it extremely difficult to play the left hand legato meaning I would have to learn to "hit" my hand on the keys on each of those 2-note chords. I guess its important to have a constant fingering for them, as the switch between 2-1-2-1 and 1-2-1-2 always resulted in exaggerated velocity due to lack of control which came from having to hurry the 1st or 2nd finger onto those chords. Again, thanks for the insight.