With H-shem's help, we have begun learning Hilchot Tzitzit with the Ben Ish Chai, Hacham Yosef Hayyim of Baghdad. The sefer is translated by Shmuel Hiley and published by Yeshivath Ahavath Shalom Publications in Jerusalem 5765/2005. He calls the names of the Chapters by the names of Parashiot, so instead of Chapter One, the first chapter is called Parashath Bereshith, Laws of Ziziyoth. Please note these are for learning purposes only. For the halacha lemaaseh, i.e. for what to do yourself please ask your own Rav. So let's begin:
Parashath Bereshith, Laws of Ziziyoth, Page 1-2
2. The wording of the berachah on the tallith gadhol should be lehithattef BEzizith; -- not 'BA-zizith'.
If, in the morning, one is still wearing the same tallith qatan that one wore throughout the previous night, it is correct not to recite a berachah over it, but to have it in mind when reciting the berachah on the tallith gadhol, and the same berachah will cover them both.
(The reason for this is that not all codifiers maintain that one may recite a berachah on the tallith qatan in the morning, if it were worn all night. We must therefore apply the rule that 'whenever there is a halachic doubt as to whether a berachah be recited or not, one rules leniently and does not recite it.' Nevertheless, I write in my work Meqabbeziel that it is advisable to have the tallith qatan in mind as well when reciting the berachah on the tallith gadhol.)
Since it is possible to forget to have the tallith qatan in mind before reciting the berachah on the tallith gadhol, it is best to add the following to the text of the Leshem yihudh: I am preparing myself to recite the berachah which our Sages z'l instituted to be recited when draping oneself in the tallith gadhol, and I also have in mind that the berachah over the tallith gadhol should include the tallith qatan.'
There is no need to touch the tallith qatan when reciting the berachah, even according to the opinion of Maran z'l [as explained by the author in his work 'Odh Yosef Hai (1) in detail.]
This learning should be in memory of Maran, HaRav HaGaon Ovadia Yosef, ztz'l.