After seeing the parts that make up the 360° x 180° head, the logic behind the simple head should make more sense. Chances are with the exception of horizontal rail the head can be made up with what you already own.
A. Pistol grip - 3 point level.
Notice the level at the bottom of the grip. Any tripod head should work as long as it can be locked in position. If not practical, the tripod legs can be used instead.
B. 360° ballhead with degree markings - Rotator.
A video head also works well. The degree marking are not as important as being able to rotate 360° without the chance of moving vertically. The rotor must be perpendicular (90°) to the top of the head.
C. Horizontal Rail.
The 360° x 180° head shoots vertically while the simple head shoots horizontally. At the workshop I’ll explain way. Here I’m using a Exmax 26cm rail. Any rail will work as long as the lens can start behind the center of rotation and move forward.
D. Level.
The camera’s internal or an external level can be used.