On the morning of Simchas Torah, in the synagogue I attend, we recite Birkas Kohanim during Shacharis rather than Musaf. I asked around, and was told that because many people make Kiddush before Musaf, the custom is to recite Birkas Kohanim before drinking alchohol.
I have seen some support for this. I believe that in the Mishneh Berurah, at the end of the discussion of Simchas Torah, there is some remark about drinking and Birkas Kohanim.
On other holidays, during Birkas Kohanim, the Kohanim chant a wordless tune near the end of each of the blessings, and while they chant the congregation recite a text. This whole business is omitted on Shabbos, because (I’m told) it is considered a personal request. It is also omitted on Simchas Torah. When I asked around, I was told (in a tentative way) that perhaps the omission on Simchas Torah has to do with the switch from Musaf to Shacharis.
I’m not sure I understand the logic that allows us to say the prayers of Musaf itself, but not the Birkas Kohanim, after drinking. It has to do somehow with the status of the Birkas Kohanim as being "from the Torah"?
In at least some non-Shabbos-Simchas-Torah-Shacharis-&-Musaf services, why don’t the Kohanim chant, and why doesn’t the congregation say the associated text?