Kesher Shel Yad

What is the Minhag Frankfurt to form kesher-shelYad? Is it standard Ashkenazzi knot or Chafetz Chaim knot (Lita) or R'Eliyahu knot (Chabad)?

My great-grandfather, who grew up in Fürth wore a kesher Chafetz Chayim, however this was on a pair of tefillin which he purchased in Boro Park after the war, so the sofer may have tied according to his (Litvisch) minhag, rather than ours.

Noach

What about its placement? Most communities are makpid to have the kesher directly abutting the ketzitzah, which I've heard is based on the Zohar.

What do the different knots on the shel yad look like? Can the picture of an Ashkenazi knot be posted?