Joy and Magen David

Chuppa stone ritual, Nuremberg 1726 
From a book by P. S. Kirschner

Here's a copy of the letter I sent to Rabbi Reuven Lauffer at Ohr Somayach Yeshiva:
It seems that there's a deep connection between Joy and Magen David.
Recently I read about The Chuppa Stone beside the entrance of the old Freudental synagogue in Germany. On this Chuppa Stone the groom had to smash his glass of wine in memory of the destruction of the temple in Jerusalem.
I also read that researcher Falk Wiesemann found in Germany twenty-two such stones and on many of them there was engraved a Magen David.
On Wikipedia I read that many Ketubah designs incorporate religious or secular symbolism, such as the Magen David.
On your website I read that

Some people have the tradition to hanging a Magen David in their Sukka. Perhaps the six sides allude to the six "Ushpizen" guests who visit during the first six days of Sukkot: Avraham, Yitzchak, Ya'akov, Moshe, Aharon, and Yosef. The star as a unified whole symbolizes the seventh "Ushpizen" -- David -- the "king" who unifies the whole. Furthermore, the Magen David has 12 sides: David as king unified the 12 tribes.

IMHO the Magen David symbolizes Jerusalem (Zion) which is remembered by the Jewish people especially when they have the best reasons to rejoice… Sukkoth is a most joyful holiday, wedding is a most joyful event and yet - "If I forget thee, O Jerusalem, let my right hand forget her cunning" [Psalm 137:5[
Since I'm a secular Jew and since I'm not an expert on these matters I'd like to know how you comment on this theory.
The answer I got from the Rabbi was short but encouraging:
Sounds beautiful to me!
Best regards from Jerusalem,
Rabbi Reuven Lauffer