Hey Danandteri,
John Played out of all kinds of positions, and used the capo quite a bit with open chords. Keep in mind that all open chords can be moved too, not just the barre chords.

I didn't mean to offend you, I just know that the way I've learned most everything is to learn the way the song goes. Once I know the basic chords, then I move the triad until I find the position that sounds the same. You will have to train your ear to hear the differences in pitch, and the difference in a wound string, and plain steel. It's not as hard as it seems, and you'll have to teach yourself to hear music this way. It is possible for someone else to show you this, but they would have to call your attention to all the details.

I'm not saying you have to learn all the songs either, just the one you first heard the pattern in. Learn that progression, and then figure out the position on the neck. Then you can pick out the pattern, and apply it to other songs. You may find that the picking patterns vary more than you think.

I recently did tutorial on crosspicking, and here's the link to it.
http://www.guitartricks.com/tutorial.php?input=1011

This may help you hear the different tones on wound strings, and plain steel strings. It will probably also help you hear the difference in a fretted note, and open strings. I wish I could do more to help, but I don't even know the name of the song(s) you heard. I know it can be frustrating, and I'll keep trying to help you.