Supported Pieces for Rhapsody No. 2 AND Grand Gallop Chromatique.

[pianokai]

Hi guys.
First question post from me. Just a quick background so you know where to base your answers: Playing since 7 (I'm 25 now) went to Chetham's School Of Music in England (Apparently that labels my base skill somewhat but I don't think it does speaking modestly!) And my repetoire are pieces like Rachmaninoff Prelude G minior, C sharp (the first page one) Chopin A minor (I think) etudes and 3 others on the same OP, Chopin Fantasy Impromptu, played and performed.

So ok, you know I can play and I like to CHALLENGE myself. I can sight read ok, (at the standard of skimming first page of grand gallop chromatic no problems and can play pieces without learning it like beethovan's moonlight sonata first and second movements)

So heres the question.

I want to learn the hungarian rhapsody no 2 (I can play slowly and sketch out the notes til halfway through friska) and can do first 4 pages of Grand Gallop Chromatic and get stuck on the "thirds" semiquavered area (shiver)
I KNOW I need to work on Hannon and Scale, but what other supporting peices can I learn, to help make the technicallity of these 2 monstrous pieces easier? Also I am self taught now. Bryan