Plumbing in space

I've been really excited for the last few days, since NASA launched the STS-116 mission, including the Swedish (Norwegian?) astronaut Christer Fuglesang. This evening I've been watching NASA's TV-feed while Fuglesang and Curbeam try to do some re-assembly and assembly of some of the gear they brought up on the mission to complete the International Space Station.
I suddenly realised why I would not have been suited for the job. Part of the conversation the two guys had with Houston was asking if they would be allowed to use a different sized wrench to untighten a bolt. I would surely have picked the tool I found appropriate and done the job. I guess from the likes of NASA's point-of-view, that would be unacceptable frm a disciplinary point of view.