This guy has it right. Its all about the tools.
Setting up gears isn't very hard, Setting them up correctly is whole other story.
Factor in the high dollar amount associated with the special tools needed to set up gears correctly with the lack of interest in this thread. Also, gears and lockers aren't cheap. Why risk that much money by having the gears installed by someone who doesn't know what they are doing?
I understand you want to learn. I might suggest checking out the Las Positas College auto shop program, you would probably have to enroll in the class to use the tools.
Best bet would be to bite the bullett and pay to have them installed. I know for a fact the tools I use to set up gears cost more than I would have spent on having my gears installed at a shop.