I had to make some instrumental substitutions. I don't really have access to a good synth sound (a Moog is near the top of my instrument wish list), so I used the B3 bass pedals setting on my keyboard. The string parts are both mellotron sounds (violin and cello). Some of the violin part is triplets, which are a bit difficult to play; I did my best.
I recorded this more from memory than anything else. I vaguely remembered this post from a couple years ago in which I mentioned that - while they're similar - the lower string part isn't exactly the same as the synth part. Had I lookt at that before I recorded my audio example, maybe I would have thought to reference the instrumental mix (a bonus track on the CD re-issue) for greater accuracy. I'm pretty confident of the synth part and what I have of the violin part though.