Hello - Kosher Java has published the code for the zmanim used by the Sephardic community, based on the calculations of Hacham Yosef Raful.
These are the zmanim exclusively used by all members of the Syrian community, and I presume most other Sephardim as well.
These are based on the Magen Avraham, in contrast to the current calcs based on the Grah.
I was wondering if it would be possible to offer the Magen Avraham calcs as an option for your siddur?
Much thanks, Victor