You'll have no problem with the technical side given your ability/level. Think Phrygian. Get a recording (do you read a decent level notation? Do you work with any classical repertoire?) of Rodriguez Concerto de Aranjuez. It's often used as a source of Spanish sounds particularly on this song. Maybe begin by playing around with a particular progression of chords that leads to a cadence somewhere in the actual song. You'd like to keep it airy (read: rubato), maybe something not too fast to set up the intitial figure of Spain, let that be a surprize.
Let the sound/feel of your chosen chords determine a melody. You're good with arpeggios, and you do a nice kind of pedal thing in your piece- be inspired by what you know. Rewrite parts of your piece in phrygian and see how it sounds.
Some pieces by Albeniz, try Leyenda or Asturias, particularly the transitions into and out of the quiet passages. about 1:20, a little flourish, a dramatic pause... and the opening passage of Spain...
' just a few ideas. Hope it doesn't muddy the pool.
David