How early on Leil Shavuot can I begin learning the Sefer Tikkun Leil Shavuot? Can I start while it is Shabbat and be mafsik for Ma’ariv, the Seuda, etc,..?
Can I continue after Mussaf if I don’t finish?
The Tikun Leil Shevuot like the name indicates should be said on Shevuot. If you don’t manage to finish it all by night you can finish it by day, Gut Yom Tov!