Tefillin Parshiyot

It is my understanding that, today, Ashkenazic Jews from Eastern Europe -- and to my knowledge, many from Germany -- follow, by and large, the rulings of the Taz with regard to the open and closed paragraphs in the parshiyot of tefillin. The Taz's ruling -- and again, I may be wrong -- was an attempt to reconcile a machloket between the Rambam and the Rosh concerning the number of spaces needed to constitute a setumah. In essence, the Taz's ruling was a compromise, a combination of the two opinions, and according to modern Ashkenazi poskim, one that satisfied both Rishonim's opinions. (Though today, the vast majority of Sephardic poskim consider Ashkenazi tefillin pasul for this very reason).

My question is this: What is the Ashkenazic (that is, German/Yekkish) tradition for the setumah in tefillin parshiyot? Do Jews from Germany follow the original opinion of the Rosh, or the later opinion of the Taz?

(Please do not consider my version of this debate in any way authoritative -- or even reliable. It is just the history of the matter that I pieced together from various sources).

Thanks!

DBeckman

Is the opinion of the Ta"z the version described in the Mishnah Berurah, or that described in the Igraus Maushe?