I am no scholar concerning Jewish feast days or leap years so I can not give you a solid answer to your question from your post.But your question about what day the abomination of desolation might fall on did get me to focus on some possible scenarios of that and other dates.If I am correct (from my graph below) and that the arrival of God's two witnesses initiates the start of the 7 year tribulation period....... then when might the two witnesses show up? What Jewish feast day mandates that two witnesses witness the arrival of the new moon?....... Rosh Hashanah When is Rosh Hashanah celebrated? It varies but normally in....... mid September.So from my chart if God's two witnesses showed up in mid-September as the start of the 7 year tribulation period and (from my chart) the rapture happened 1335 days later, where does that take us? Rapture in late May or early June. Does that make sense scripturally? Yes, The Song of Solomon and Isaiah 18 both indicate that Jesus comes for his church in late spring.Then from my chart .....assuming that the two witnesses arrive on Rosh Hashanah......when would the abomination of desolation happen? As per the chart, it would happen around mid-February. Does that make sense scripturally? In Matt.24:15 Jesus is speaking to the Jews about "the abomination of desolation" and instructs those Jews to immediately flee to the mountains if they see the "abomination" being set up in the holy place. Then Jesus gives them a hint when this may happen when He says......."And pray that your flight may not be in winter or on the Sabbath". Mid-February is definitely winter and if I were a betting man I would wager that Jesus was more than just giving them a hint as to the timing of the abomination of desolation being "set up".It appears to me that the "abomination of desolation" will be set up in Jerusalem 41 months after the arrival of God's two witnesses who arrive on Rosh Hashanah. I believe this will happen in mid-February on a Saturday (the Sabbath). Once the two witnesses show up on a specific year the exact date of the "abomination of desolation" can be determined.
Blessings Gino........John B