The halachic question I have pertains to the use of Rabbeinu Tam Tefillin – I decided that I wish to incorporate its use in my daily life. The dilemma involves what minhag I follow…………. My father (ZT”L) was a holocaust survivor from Poland who was a yetom and grew up without any specific religious tradition, although being that he and his family were from the town of Wyszkow, it is highly likely that they were part of the Radziner Hasidic dynasty as most of the inhabitants of the town were Hasidim with Radziner being the majority (Wyszkow also included Gur and Alexander Hasidim). My mother (who was born in Israel) is of Sephardic decent as her father was born in Bukhara (with the family likely having migrated there from Persia as his father held a Persian passport), and her mother hailing from Izmir, Turkey (with the family tracing back historically to Florence, Italy and prior to that likely being from Spain). My parents themselves were not particularly religious, but when it came specifically to Pesach, we would consume rice (as per my mother’s family tradition). The Rashi Tefillin I currently own was purchased by my father and is Ashkenaz. I daven daily using Nusach Sefard, although on Shabbat I use Nusach Sepharadi. My tallit kattan (Arba Kanfot) is typical Sephardic with white stripes, while my tallit gadol was given to me by my father and has black stripes.
While my Rashi tefillin are Ashkenaz, my preference was to purchase Sefard Tam Tefillin but the Chabad Sofer explained it was preferable to have Rashi and Tam being the same and thus that I should therefore consult with a Rav (although I attend daily shiurim I have not yet selected a Rav with whom I personally consult). On another note, my Rashi Tefillin batim are 3×3 but I am inclined to purchase Tam that are 4×4 although I don’t know whether that would overshadow the Rashi which is the one which obviously receives the bracha (the Chabad Sofer felt that the difference in batim size is inconsequential).
Looking forward to your reply.
The size of the battim is, indeed, inconsequential.
As for the script, it is true that one should try to be consistent in this as well as other matters of Sefard / Ashkenaz practice.
In your case, the main conflict is between the nusach of your davening and the Tefillin script (it is best to be consistent in this too – though there are many who have similar differences between the davening nusach and the Tefillin kesav).
If you are planning on continuing to use the Ashkenaz parshios that you have for Rashi, then it is more correct to have the same script for the Rabbeinu Tam Tefillin too, since this is the manner by which you fulfill the mitzvah of Tefillin.