When I was a child, I saw that all people had the same knot on their Tefillin Shel Rosh - a Double Daled (Ashkenazi community).
Recently I saw a comment that even those who grew up with a Double Daled, and even if their Father's minhag was a Double Daled, that they should all switch to a Single Daled.
My questions are:
- What are the sources for this, if any?
- Why is the Single Daled supposed to be "better"? Is this only for Kabbalistic reasons, or is there a real Halachic reason for this?
- Are these poskim who require this change in minhag correct to do so?
- Are there any Ashkenazi Poskim and/or Groups today that specifically say that a Double Daled is preferable?