Spoilers!

If you choose the right instruments, then Rinoa will like the music, and her conversation with Squall will be longer. And sweeter, in my opinion.

There are two pieces of music in the jumbled-up scores: a jazzy version of 'Eyes On Me' and a jig which you may hear later at the Shumi village. The jig is the 'correct' piece. You'll need to select the violin, guitar, flute and tap. It doesn't matter who has what, as long as you choose the correct instruments.

Good luck!