How does someone decide from what direction to approach the twelve-Nidānas? From what I can gather (from wikipedia) there are four methods:


  The Twelve Nidānas are explained in detail in the Visuddhimagga of Buddhaghosa, the central text of the Mahāvihāra commentarial tradition. Buddhaghosa recounts four methods to interpret the Twelve Nidanas:



Working from "bottom to top",
Working from the "middle to the top",
Working from "top to bottom",
Working from the "middle to the source".



  The first method begins with ignorance and proceeds to sickness, old age, and death. The second method begins with attachment and proceeds to birth. The third method begins with birth and proceeds back to ignorance. The fourth method begins with attachment and proceeds to ignorance.


Given these different approaches, how can an individual decide which they are most suited to follow in order to revert the chain and where in the suttas can each approach be found?
Because I believe I understand twelve nidanas, I suggest you approach them from the bottom up.

This way, each next nidana up will be the "cause" (or, more precisely, the ground or the context) for the one below it.

As I said here, I believe the relationship between nidanas is that of implication. Be sure to check out the thoughts of Nanavira Thera and ven. Buddhadasa for useful hints. I do not agree with all of their conclusions but they are on the right path, as far as I can see.