He does use a lot of open string chords and arpeggios as well. For example, if you know the formation for the F# barre chord with the root on the low E string (second fret), rather than laying your index finger flat to make the barre, lift it so that it is only fretting the root note, leaving the 1st and 2nd strings (E and B) open to ring. Now using that chord formation, and leaving the 1st two strings open, try shifting around the fret board playing all six strings ( as a chord or an arpeggio) and letting the 1st two strings ring out. If you listen to Hemispheres he does this type of chording a good portion of the time. As for his early sound, he used to play a hollow body much of the time and with a chorus pedal, light distortion, and some tweaking you can really get close to his old sound. His solos are original in their use of chording, but he is also keen on playing single note flourishes with fast tremolo picking, pinch harmonics, and string bends. I think Hemispheres is the consumate album for the range of his style. If you can play all of that album you can probably play anything he's done before or after. He is one of my favorite guitarists, a huge influence, and probably the most underated player in rock. To me, his stuff isn't extremely difficult to play (once you can figure the parts out), its just incredibly inventive and tasteful. I know there was a tab book out at one point which covered most of their albums through the mid 80's.