If you get it down the accuracy of the notes and articulation of the left hand at slow tempo, once you go up to a quicker tempo your hand will just naturally know what to do.
I agree about the importance of slow practice, but not the part about your hand "just naturally knowing". If that was the case, everybody having the patience to play slowly enough to get the notes and articulation right would become a virtouso. I think it's certainly possible to play slowly and correctly with a technique that won't work at a faster speed. And I think nadapez does very well to consider his or her technique, questioning what will or will not work in the desired tempo.
That being said, I don't think that using the 'force of the fingers' will get you anywhere in this particular case. A feeling of 'grapping the keys' might help playing the chords crisply and accurately, but keeping the fingers always in contact with the keys I think will only make things much more difficult, causing fatigue and tension. These left hand chords isn't 'high velocity' in that sense. And I don't know why you would strive to play them 'non staccato'?