So, here's what Johnny Marr shared in response.
I love the tracks you did with John Frusciante on his album, The Empyrean. John has such a distinct musicial vision. What was it like collaborating with him?
John is always keen to avoid the obvious. He's someone who's very into emotion in music. He has idealism about sound. When I worked with him on that record, he struck me as someone who was always searching. He's not at all blase. If you're hearing him playing a sound that is very clean, to John it's the result of him looking for something that's pure. Every sound he puts together is deliberate and meaningful to him. When we did those songs he inspired me, so I worked very quickly. I would grab an acoustic, put it into a drone and play by ear without worrying about being too precise. I'd go with my feelings. Then for another song I'd grab a Strat and just do harmonics. He let me do a lot of textures. I don't think it will surprise anyone to hear this, but John is a very deep guy.
You can see the entire interview on Johnny Mar's official website, if you're interested (and you probably should be!).
*Many thanks to Sophie for having asked the question, Tom for the heads-up and Johnny Marr official website for the scans this was transcribed from.