For panoramas using just a ball head - there is a pretty simple approach to this. The problem is that most ball heads are not designed to support it.
It comes down to two items:
- The ability to pan level
- For perfection - the elimination of parallax, you need a nodal rail so that the camera sits back from the rotational point and the lens main element is over the center of the ball head. Panoramas are just fine being taken on just a ball head - unless there is something in the foreground and then that will throw the stitching off.
The secret to panning level is to have the "turn table" above the ball head and NOT in the base of the ball head. If the turn table is in the base, then the tripod needs to be setup level so that you can pan level. The ball head is then of no real use. If the tripod is just off level, then the base of the ball head will not pan level, and the camera on the top of the ball head will track in something like an upside down U - from side to side.