I agree this is a difffcult piece, technically, but it is worth the effort.
Being a fan of Liszt

, I would recommend you persevere with it, even if you do not play it in your Grade 6 exam. However, you may need a strategy in place to allow you to practice all the seperate lines of the piece, thinking almostcontrapuntally. And tackle the most important lines first - RH top line melody, LH bass notes on the beats.
A few ways of practising this piece which you could try....
Play the RH melody (top notes)
on its own, using the fingering suggested and making sure its
legato;
Play the bottom bass notes (1st beats of bars), while 'miming' the upper bass notes (place your hand in the right place but do not press the keys down): this allows your hand to be prepared for the position changes, and gets you used to landing on the upper bass notes in plenty of time ready to play them;
Play the Melody (RH) with the bottom bass notes (LH) only, to get the harmonic stresses really strongly felt in your mind, ears and fingers;
Then tackle the inner parts - RH lower notes, played on their own, correct fingering, then LH upper notes the same: remember these are
not played on the strong beats, so must be shaped accordingly, and voiced gently to sound
softer than the top and bottom lines;
Then try RH, playing
both lines together (all notes - slowly), weighting the sound towards the TOP to make the melody sing
cantabile;
Then try LH, playing
both lines together (all notes - slowly), weighting the sound towards the BOTTOM to ensure the bass notes accentuate the harmony (note: a pedal note for the first three bars);
Think about all these lines when you come to start putting it all together, but only do so
two lines at a time at first, so e.g. play RH top line, with LH top line (keeping the balance towards the TOP), then try RH bottom line, with LH bottom line (keeping the balance weighted towards the BOTTOM) etc;
Then try three lines together, and finally all four.
Take your time over the arpeggiated chords (bars 9 onwards), making sure to voice all the notes clearly. The top notes need to sound most strongly again, so be sure to hold these out
tenuto.
The octaves present another challenge (bars 16 onwards) so play these slowly, practising them with geat care.
Finally think about dynamics, looking for the main climax in the piece (which will be 'built towards' using increasing dynamic levels). Individual phrase shapes will also dictate dynamics: so, notice that the first phrase (first 8 bars maybe ?) has its highest point somewhere in the middle - try starting the phrase perhaps pianissimo then crescendo into the middle (bar 4 perhaps) before using a diminuendo towards the end of the phrase. This may not necessarily be ideal for each phrase.
Other posters will have lots more ideas for phrasing I'm sure.....
Good luck,
denmark