Sofer STA"M Kaballistic Expectations

Is it expected that sofrim who write mehudar STAM (Sefer Torah, Tefillin, and Mezuzah parshiyos), that they should write while having in mind the kevanos of the Zohar and Arizal?

Halacha mandates that the sofer writing Hashem's Names must verbalize before each time that he is writing 'Leshem Kedushas Hashem'.[1] The Zohar is very stringent in writing Hashem's Names with special kevanos by all STa"M.[2] On the same note, poskim write that if one does not master these intricate kevanos properly, it is better not to do them, as it is worse to write them with the kevanos incorrectly than to write without the special kabbalistic kevanos.[3]

Sephardic and Chassidic sofrim (those who write ksav Arizal and Admur Hazaken) generally follow the practice to write Hashem's Names in hei chalukos (five parts) as prescribed in the teachings of the Arizal. It is visually identifiable when this is done. However, they do not write with the special Kabalistic kevanos.[4] Only a select few sofrim claim to write with the special Kabilistic kevanos. 

Is it a proper hiddur (beautification of the mitzvah) that the sofer should write the entire tefillin parshiyos without taking any interruptions at all?

The Ba’er Haitiv^[5] quotes from the Sefer Hakavanos that the sofer should not interrupt throughout the writing of the four passages of the shel rosh and the shel yad. There, it mentions that if this is too difficult for the sofer, he should write the first three parshiyos without any interruption. If this is also too difficult, he should write at the very least the first two parshiyos without any interruption at all.

Today, it is very difficult for most sofrim to be careful in this hiddur (beautification of the mitzvah).^[6] But at least, the sofer should not interrupt in between the writing of a single parsha. However, according to the letter of the law, interruption does not invalidate the parshiyos. Rather, one just needs to write the parshiyos in order with the required kevanah.^[7]

[1] Shulchan Aruch (Orach Chayim 32:19).

[2] Zohar Vayikra 19b. See also Birkei Yosef (Shiurei Bracha 270:2).

[3] Divrei Chayim (Yoreh Deah 1:57); Imrei Shefer (Klal Alef:19);Kol Yakov (Yoreh Deah 276:6).

[4] Kol Yakov ibid, suggests as such and writes that so was the custom of sofrim in Baghdad.

^[5] Ba’er Haitiv 32:3, also quoted by the Shaarei Teshuvah 32:3.

^[6] See Lishkas Hasofer 20:6 in the name of the Meleches Shamayim Klal 17:10.

^[7] See Piskei Teshuvos (Rabinowitz) 32:2.