And in english....................

1) The size of the master cylinder would be more critical. 7" boosters are used all the time.

2)Usually all you get with the power window kit is the regulator, a switch with some wiring, and the channel that attaches to the bottom of the glass to connect to the regulator.

3) Only on a farm truck.

4) Only make it yourself if you have a big enough lathe to make precision cuts and the balancing equipment to keep it from shaking your teeth out. Most good drive shaft companies will supply you with a drawing to show how to measure correctly. You'll need the slip joint for your trans to help be more accurate. Or, you could use a 4x4 like Spraytech.