The Rebbe's rulings and clarifications on the laws and wording of berachos and on Birkas Kohanim:
Wording and practice of berachos. For Birkas HaChama, recite "Oseh Ma'aseh Bereishis," as the Rebbe and most later authorities hold, following the Alter Rebbe's ruling on the blessing over thunder in his Seder Birkos HaNehenin (IK 2068). Whether Shehecheyanu is said at a bris milah depends on the custom of one's community, not on where one lives (IK 7727). Established wording and customs of blessings should not be changed lightly (IK 5765).
Birkas Kohanim (duchening). On whether a Kohen with a defect in his hands or fingers may duchen, see the detailed analysis in IK 15; on when the Kohanim turn and say their prayer, see IK 2710. A Kohen's blessing cannot be directed to someone who has passed away, unlike Tehillim (IK 1231). For duchening customs in Eretz Yisrael, including on Yom Kippur, ask the local Kohanim of Anash, who surely have a tradition handed down through the generations (IK 5895).
See also: Prayer – Nusach (prayer version) and prayer customs; Halachah and custom – Customs and minhagim; Bitachon – Receiving a blessing: making a vessel for it.