Buy some good spanners, they are worth the expense after the 2nd lens you open up. I was very appreciative to receive both the blade type and pin type from SKGrimes for Christmas and they've been enormously helpful.
I would also advise drawing out or photographing each step of the repair as you do it. If you can look up the specific item you are repairing, there may be notes on disassembly and possibly a Youtube video.
Other tools/supplies I can recommend: Ronsonol or Naphtha for element cleaning and general grease cleanup. Grease that doesn't break down in heat, Tri-flow as a light lubricant/drop some on stubborn screws to help break them loose, Simichrome polish (if the coatings are damaged/hazy or you want a full polished look on aluminum surfaces, also works as a paint polish and cleans chrome bodies like Pentax or Leica cameras without changing the surface texture.
Oh, and #1 supply tip: Buy stock in q-tips, then buy in bulk.
Filing down screwdrivers to fit correctly or creating your own tools is part of it as well.
I just did a 90/4 Elmar for a friend, no big surprises and it cleaned up rather well. Still gets beat by the 100/3.5 Canon as far as image quality but that's not a surprise either.
