Kind of like what Donny said:

I download the original and play it on my laptop. The first thing is to get the correct tempo. From there, at least on my 3K, I try different styles by changing the style while playing (to keep the tempo default). I am working on a 50's medley and others and do it this way - works great for me.

As Dreamer said, I end up muting tracks to keep it clean and utilize my variations, endings, intros to the max.

I was up till 1:30 am doing this sort of thing - time races by

Good luck.