Waltz Op.34 N.2 fingering question

[diedel]

Hi there,
I'm trying to play this waltz since I dont remember when... 
Surprising,  the more difficult passage for me is from bars 17 to 22 aproximately. I can't get the sound I want. I have played the left hand bass with the 5 finger for the more low note of the chord, later I've changed to the 4 finger and recently I've returned to the 5 finger. I find my hand more relaxed. What fingering recommend for this bars, 17 to 22? I have a little hand.

Thanks and regards.