Good post Jason.
The old belt would not have stretched that much that your timing marks are out. Any stretch in the belt is compensated for by the belt tensioner. Otherwise the engine would not run.
The most important steps are -
1. Line all the marks on the pullies and the block up.
2. Use a marking pen to clearly mark the belt at the pully marks.
3. Release the tensioner, and remove the old belt.
4. Transfer the marks on the old belt to the new belt, using the number of teeth as the guide.
5. Fit the new belt lining up the belt marks with the pully marks, and clamp the belt in place using butterfly clamps (from your stationary supplies). Then release the new tensioner and the slack goes out of the new belt and everything should line up.
If you have started from the wrong position, the link Jason attached will explain how to get it all back in line.
Good luck.
PK