Oh...well, honestly, I'm probably not the best example as regards what to do with this piece...many years ago I learned it in 3 days and played it in a masterclass conducted by a famous Chopin musicologist...needless to say, he wasn't pleased by what he heard...at all

Anyway, I constantly looked back at it sporadically and decided to learn it properly recently. Right now it is firmly a part of my competition warhorses. Throughout the latest learning process, I actually find that by prioritising musical aims first and foremost, one will achieve a pleasing result and will eliminate many technical problems. So that's my tip to you: worry about the kind(s!) of sound that you want in the LH...worry about the melodic phrasing...work on achieving them on the piano. That's how I'd approach working on that RH passage you mentioned you had some problems with. Not the other way around (that is, worry about playing all the notes correctly and up to speed).
Of course, the ground works are important as well. To finally answer your question, yeap I spent time practising the LH with/out the pedal in dotted rhythms, then slowly with different articulations. But it's all done not in order to achieve a certain speed, but rather, to achieve certain musical goals, of which speed is but only a part of. Trust me: with this piece, you will get the desired result by thinking musically, not technically!
...just my 1am 2 cents ^^