you sound like u've got more expertise about recording than i do, too, and i hope that u'll get all the sound that u want from the lh and places where u want to bring out particular harmonies. this is really a beautiful piece and it did make me think i was eating a fine dessert. it's not often we get to critique such a difficult piece and played without bashfulness.
perhaps u might add to our understanding of the piece the reason why it sounds like a blend of 'climaxes' of many different styles - all put into one piece. is this the idea that scriabin was using to create this fantasy (so many different ones) and is this fighting the tradition one or two climax idea? it loses my attention if there is more than two - but, then, again ... i might be listening with a traditional ear. i definately heard a different 'tone' in the 'breaking the clouds' section at the beginning. i thought it was extremely beautiful. but it wouldn't follow the ABAB pattern of stormy, cloud clearing, stormy... so how do u create a difference of feeling in the other sections? i personally feel that it is ignoring the absolute rh melody lh harmony idea in favor of just picking a line and bringing it out in some sections. for instance, making one section be about hearing the tenor line - or the bass a little bit more (still allowing freedom in the rh to 'soar' - but allowing the ear to be tricked). just random thoughts in my head.
Wow, that's a really intellectual post...
i shall try my best to answer it....
although it's called a fantasy, the individual sections (which you have labelled A and B) of this piece are quite clearcut (Scriabin makes it very clear by assigning different metronome markings at the start of each section), unlike other fantasies with really random and unpredictable mashes of ideas.
If i were to analyse it, it would be ABCA'ABCA'BA, with A being the mysterious opening, B being the sweet lyrical "cloud clearing" in D major, C being the ferocious storm. But then comes the complicated part.
Because the next quiet section uses the same motivic idea as the opening, but modified so much in harmony and voice that it sounds like a new idea, i label it A'. This is then followed by an embellished version of A, with underlying ripples. The sweet melody (B) returns, but this time as a loud passionate octave passage in B major. After the expected C section, we again move back to A', this time in a very reflective mood. The piece stays in the soft register as B returns once more, again embellished by semiquaver LH. Finally, a triumphant A section returns to conclude the piece.
although technically speaking there are three sections, but each time section A returns in a totally different character, though utilizing the same thematic material. Same for B. Only section C stays constant for both times. To complicate things further,

sections A and C share the same rhythmic motifs at times.....
Within each section, Scriabin always have some sort of building up. To me, I would regard it as one long ocean wave rather than "many mini climaxes" as you have described. Sometimes, the waves will build up to an extremely high point, sometimes just a small ripple. But the important thing is each individual section does not stay flat or stagnant. That's the reason this piece does not sound boring. Rather, the listener is always being carried along by the wave to its highs and lows.
(right, i am tired)

hope this helps!!! please do listen to the piece again, and see if my "analysis" fits the bill....
thanks....
ps: nah, i am not at all experienced in recording! this is my first attempt at cutting an album.