LIFE back cover (PT1) OCR evidence from Google Books Click3 page images:
Jan 9, 1970 (id j1AEAAAAMBAJ): "Put Tareyton's activated charcoal filter..." => Tareyton.
Feb 6, 1970 (id Y1AEAAAAMBAJ): "IN CASE OF HOT TASTE BREAK OPEN KOOL" / "Come all the way up to KQDL" => Kool.
Feb 13, 1970 (id ZlAEAAAAMBAJ): "...about Lark's Gas-Trap filter." => Lark.
Jan 28, 1972 (id D0AEAAAAMBAJ): "Benson & Hedges" => Benson & Hedges.
Feb 4, 1972 (id EkAEAAAAMBAJ): "Get the full taste of Viceroy." => Viceroy.
Feb 11, 1972 (id E0AEAAAAMBAJ): OCR "TARK" on back cover Lark ad => Lark.
Feb 18, 1972 (id clIEAAAAMBAJ): "Come to Marlboro Country" / "Marlboro" => Marlboro.
Feb 25, 1972 (id cVIEAAAAMBAJ): "PALL MALL GOLD 100s" => Pall Mall.
Mar 3, 1972 (id dVIEAAAAMBAJ): "Spend a milder moment with Raleigh." => Raleigh.
Mar 10, 1972 (id d1IEAAAAMBAJ): "WINSTON'S DOWN HOME TASTE!" => Winston.
Mar 17, 1972 (id fFIEAAAAMBAJ): "If you think all menthols taste alike... Come all the way up to KQDL" => Kool.
Repeated brands across listed issues: Kool (Feb 6, 1970; Mar 17, 1972) and Lark (Feb 13, 1970; Feb 11, 1972).