MJ,

Observing the cam lobes should get you close enough to TDC. The 72 degrees are not marked on the vib damper. There is a degree wheel that goes on the cam for exact measurements but you probably don't have one and don't need that accuracy. The camshaft alignment marks must line up so #1 is at end of compression stroke ( beginning of power stroke).

Possibly they want you to have piston at the top because that is usually where the wear in the cylinder is the greatest.

Start with #1 cylinder and follow the firing order and you will have to turn engine only 1 revolution. If you want to do the test a second time you will have to turn engine 1 full revolution before starting again. Always turn engine in clockwise direction facing engine from front. Best way is by using a 27mm or 1 1/16" socket wrench on crankshaft bolt.
P E H