Been a while since last post. I said I would be messing around with shims to see what happened, but I never got around to it, until yesterday. I revive this one because it may help someone else in the future.
I decided to get rid of that damn string buzz once and for all. I wanted to eliminate all possibilities from where the buzz could appear. First, I took the bridge of, cleaned it, and put it together. I made sure there were no loose parts afterward. I put on new strings, tuned up, and tried it out. Still the annoying buzz was present, so the bridge was not the problem.
Although I could see the strings not touching the first fret when ringed, I raised the nut by putting another shim under the treble side (just to be 100% sure). Still no difference.
There were only one thing left to try: I took out the "new" shim and the wooden shim that was there from the start (the wooden shim was as wide and long as the underside of the nut, and supported it entirely). I cut off a thin piece by it's length from the wooden shim and placed it as close to the fretboard as possible under the nut. The result, after tightening the screws, was a nut with a steeper angle due to missing physical support underneath the part of the nut that's closest to the tuners. This fixed the problem entirely.
So, if your floyd-equipped guitar mystically buzzes when you play high e's and/or b's, you may want to try this "fix"