We offer half dozen tzitzit tying and techelet tzitzit tying customs on all of our tallit and tallit katan products: Ashkenazi, Sephardic, Yemenite, Chabad, Arizal, Rambam, Vilna Gaon, Sefer HaChinuch, Tosefot and Raavad. However, one tying custom we do not list as a standard option is Ben Ish Chai tzitzit. Here in Jerusalem I have come across quite a number of Sephardim who follow this tzitzit tying custom.
We have tied tzitzit according to the Ben Ish Chai a few times when customers requested it.
In some ways, Ben Ish Chai tzitzit are similar to Chabad tzitzit. With Sephardic tying, you have single winding and loop the shamash through each, which creates a spiraling ridge. With Ben Ish Chai it’s the same, only the single windings are linked into groups.
When you tie Chabad, instead of doing single windings, the shamash loops through one, two or three windings. This creates a straight ridge. Chabad comes out with the windings snug up against one another (i.e. if you look on the side without the ridge it looks almost the same as Ashkenazi), whereas with Ben Ish Chai you see a bit of a gap from one group to the next.
Below is a video by Rabbi Daniel Cohen showing how to tie according to Terumat Hadeshen, which is essentially Ben Ish Chai tying with techelet. If you just pretend the tzitzit strings are all white you can get a good idea of how it looks. In fact, you can see the knots very distincly because they are blue. In the video he separates the chulyot a bit more than I’ve seen others do.