Working on getting my rebuilt engine and new distributor set up.

Curious about two things:

#1) What is the proper orientation or alignment of the distributor? (is the #1 cylinder position roughly 3 o'clock, where 12 o'clock is the fornt of the engine... or more like 2:30 or 3:30?)

#2) How will I know if I've got the distributor installed 180 degrees off?

Thanks!