Thus the Torah preceded [the creation of the world] by these six things, viz, kedem [the first], me-azof old] (Proverbs 8:21), me-olam [from everlasting] (ibid. v. 22), me-rosh [from the beginning], and mi-kadmei [from the earliest times], which counts as two.
Sound like he is referring to the first passage I quoted. Here is a fuller version.
4. In the beginning God created. Six things preceded the creation of the world; some of them were actually created, while the creation of the others was already contemplated. 2 The Torah and the Throne of Glory were created. The Torah, for it is written, The Lord made me as the beginning of His way, prior to His works of old (Prov. viii, 22). 3 The Throne of Glory, as it is written, Thy throne is established of old, etc. (Ps. xciii, 2). The creation of the Patriarchs was contemplated, for it is written, / saw your fathers as the first-ripe in the fig-tree at her first season (Hos. ix, 10). 4 [The creation of] Israel was contemplated, as it is written, Remember Thy congregation, which Thou hast gotten aforetime (Ps. lxxiv, 2). [The creation of] the Temple was contemplated, for it is written, Thou throne of glory, on high from the beginning, the place of our sanctuary (Jer. xvii, 12). The name of Messiah was contemplated, for it is written, His name existeth ere the sun (Ps. lxxii, 17). R. Ahabah b. R. Ze'ira said : Repentance too, as it is written, Before the mountains were brought forth, etc. (ib. xc, 2), and from that very moment, Thou turnest man to contrition, and say est: Repent, ye children of men (ib. 3). I still do not know which was first, whether the Torah preceded the Throne of Glory or the Throne of Glory preceded the Torah. Said R. Abba b. Kahana: The Torah preceded the Throne of Glory, for it says, ' The Lord made me as the beginning of His way, ere His works of old,' which means, ere that whereof it is written, 'Thy throne is established of old/
That is a more straightforward exegesis looking things the bible talks about being 'from the beginning' or 'of old'. Of course it ties it in with the mystical numerology finding six things that existed before the creation.
I was able to search for phrases from your quote
"Thus the Torah preceded " "by these six things"
and came across Rabbi Shuchat's book
here. Is that the one you are referring to? At the top of the page we get:
the word berei$hit consists of bara $hit meaning 'He created six'
Which I think is what you were talking about in the OP. However, here we leave the plain meaning of the text and start playing games rearranging the groups of letters into new words, a bit like the bible code. They take the first word in the bible, which consists of the word reshiyth first or beginning its prefix be' meaning in, be'reshiyth. It is a nice long word with a one letter prefix giving a total of six consonants, which is very handy because most Hebrew words are only three consonants long, with vowel pointings as a later addition. That is how the bible code works. Lots of random three letter combinations form Hebrew words. In this case the six letters are split into bere, which has the same consonants as bara he created (actually the second word in Gen 1:1) and shiyth which they claim means six. Maybe it does, though I did search for occurrences of three consonants shiyth in the OT, it does come up in Hebrew, but with various verbs as dress, look and briar, not as the number six. The nearest I got was the two consonant [bless and do not curse][bless and do not curse][bless and do not curse][bless and do not curse]h Dan 3:1 which does mean six, but it is in Aramaic, not Hebrew.
I don't doubt the Rabbi is conservative, but even though the method of interpretation is an esoteric hidden meaning interpretation, as long as the six are kept to things like the throne of glory, there isn't anything in the interpretation to conflict with conservative Judaism. But if you want to see where this form of interpretation really belongs retype:
"bara $hit" "He created six"
into Google and see how many Kabbalah hits you get on the first page.