I have used a similar jig in the past. It didn't belong to me though.
I will watch the videos some other time as I am in no mood to install quicktime right now.
I like this jig because the segments do not slip down after applying the glue, unlike the jigs that are mounted on the lathe perpendicular to the piece. I was working on one open segmented bowl that required me to take the piece off of the jig and true up the face and then re-mount it on the jig. I ended up screwing up the alignment of the segments. Next time I will try the lathe mounted jig.
Chinese Proverb: Man who eats many prunes gets good run for the money.