This is not even a close call nor tough decision; Siyum haShas is clear cut obvious choice.
Especially after we read Kedoshim today {& last week in Israel} where best venue for Kedusho & Sanctifying & Hallowing HaShem is by a major “Adas Yisroel” = Assifo, such as 90,000 seats at Meadowland stadium for the Siyum haShas; Not to mention that our wives can also be there and be part of this Sanctification & Hallowing of haShem as we recite Kerias Shema at Ma’ariv, and answer Kedusho & Kaddish.
There are only 2 places that anyone should be at the time of the internet Assifo:- 1) At the Kossel for Yom Yeusholayim, or 2) Kever Shmuel haNovi in honor of his Yohrzeit, or of-course both, but certainly not in Flushing. If unable to be at one of these 2 locations, at least be at the Kossel via webcam, and Daven in spirit of seeing the Kossel live, for restoration of the Beis haMikdosh soonest!
Even on Tish b’Ov where clearly I don’t fool around on the internet, but I do keep looking into Kossel webcam during Tisho b’Ov, to keep my mind focused on the Kossel & upcoming 3rd Beis haMikdosh.