I know the answer is 2,711. But I did a quick check of the dates of all 12 siyumim and used excel to calculate how many days apart they are. The last 5 siyumim were, in fact, for 2,711-day cycles, but the first 7 seem to be 2,702-day cycles. Does anyone know what changed?
The answer is that they changed which print of Mesechta Shekalim is used (which is the only mesechta of Yerushalmi in the cycle).
The original cycle used the Slavita print. It was subsequently changed to the now standard Vilna print which is longer, as there are more meforshim on each page.
It has to do with the version of the Shas that was used. For one mesechta ( I don’t recall which one), they started using the Vilna edition which has 9 more blatt at a later point. Hence the difference of 9 days. The magazine, Hasiyum, had a comment about this.
Sheqalim which technically is Yerushlami & not Bavli, did not use to be on Bavli Daf Yomi calendar. I believe by 3rd or 4th cycle it was added, for sake of completing Moed, like Mishnayos Middos & Kinnim were added for sake of completing Kodoshim.
bp27: Why did they use the Slavita print? Was that the standard for Yerushalmi before the Vilna? If so, how did the Vilna take over? And why did it take so much longer for the Vilna to become the standard Yerushalmi than for the Bavli?
Apparently I stand corrected. My guess was Kinnim and Middos because, while those are in the standard prints of the Vilna Shas and count Daf numbers, they are only Mishnayos and contain no Gemara (just like all of Z’raim is in the back of a standard Brachos and Taharos in the back of Niddah). But apparently that wasn’t the difference.