Again, the methodology of your work should be in strong accordance with the initial thesis and the main aim of your research. Visit the university library - the librarians might be eager to provide you with a good textbook as well as with a recommendation on how to start a cover letter . Thus, a lot of books can teach you research philosophy, so that you will be able to choose methods on your own. Moreover, it is convenient to look for someone else's thesis methodology example in the library. Remember, only deep theoretical knowledge can help you to reinforce your dissertation with firm methodological underpinnings.
Siri himself was never part of any split, and remained true to the established church.  He was appointed president of the Italian Episcopal Conference by John XXIII in 1959, and remained in the post under Paul VI until 1964.  He sat on the Board of Presidency of the Second Vatican Council from 1963 until its close in 1965.  He was a candidate for pope—still representing the conservatives—in the 1978 conclave that followed the death of Paul VI, where he is thought to have led in the early ballots before being overtaken by Albino Luciani (John Paul I),  and again two months later in the October 1978 conclave , where he is also thought to have come within a few votes of election.  He was Archbishop of Genoa from 1946 to 1987, and at the time of his retirement he was "the last remaining active cardinal named by Pope Pius XII."  Siri never made any reference to the "Siri thesis", nor was there any mention of it in his New York Times obituary,  in the biography written by Raimondo Spiazzi ,  or in a speech given by Giulio Andreotti on the centenary of Siri's birth in 2006.