Hello Anyone (first post),

I've just purchased a Giant Rainier 2001 frame. I get a lot more enjoyment out of building things than I do out of just buying them new, so I'm used to problems coming up and solving them. Also, I'm an engineer with a good amount of mechanical background so I don't shy away from challenging problems, but I much prefer to research things before I dive in, except maybe in that very rare situation where it just requires "quick and dirty--get it done" mentality.
So my question is: (and please give me links with further information if available so I can get up to speed) I need to know where the measurement is taken (in the head tube) which determines the size requirement for the headset. (e.g. Measure the I.D. of the existing bearing, measure the I.D. of the head tube itself). I don't have any fork with the frame and my limited understanding is that the Giant Frame has an "integrated" (I'm assuming it can still be replaced) headset. Measuring the smallest I.D. of the existing bearing installed in the head tube gives 1.178" (29.92mm). I've never looked at any of the headset measurements because this is my first bike in about 10 years (mostly into BMWs lately...no I'm not an old preppy, just like to work on them). The Marzocchi fork that I ordered is 1 1/8" which I'm assumming is the O.D. of the steerer tube. And I just thought there would be an interference fit of the fork steerer tube and the bearing races in the head tube. (Obviously, just taking one apart would probably answer all my verbage, but I don't have a complete bike lying around).
Please explain how the Giant frame is "different", what I need to do to install a standard headset (looking at an FSA pig DH 1 1/8"), reducers, etc., and where can I get these parts.
Thanks in advance for the help. The next thing I'm doing with the frame is magnafluxing it to check for stress fractures and then I need a real expert with a TIG welder to weld the V-brake standoffs on the rear of the frame. (Also, I need a contact with a frame manufacturer to get some suppliers lined up for some odd ball materials I'll be needing. Preferably in the manufacture of aluminum tubing, etc.). And finally, has anyone got a good LBS near or around Scottsdale where I can rent some tools occasionally. I've got a number of these bikes to build up with varying frame makers (mostly all aluminum or carbon at this stage), and I need to start buying/renting some tools, but borrowing would be helpful in the beginning. Specifically, I need a thread chaser and facing tool for the BBs.
Lastly, who's got some experience with X-type installations? I'm hoping to get some "throw-away" bearings for failure analysis and sizing purposes.
Sorry for the long post. :-)

-Jeff