A forum for people with knowledge of the Bible in its original languages to discuss its manuscripts and textual history from the perspective of historic evangelical theology.
You could start out looking for Psalters. These were originally based on the OG OT and tended to stay in use even after the HB was translated.In a similar way, the KJV was slow to dislodge the Church of England Psalter based on an earlier version.
I once had a look at a volume of the Prophetologium edited by Hoeg and Zuntz. It is a good critical edition of lectionary texts of the LXX. It is published in a rather obscure series: Monumenta Musicae Byzantinae. Lectionaria. Vol. I, and, if my memory serves me right, it took as the base text a 12th or 13th century Sinaitic manuscript (or Sinaitic lectionary tradition).
Actually, the complete edition of the "septuagint lectionary", or "prophetologium" comprises 8 volumes (ed. Høeg, Zuntz, Engberg, Monumenta Musicae Byzantinae, Copenhagen 1939-1981) and is based mainly on two manuscripts from the 11th century, one in Venice and the other in Oxford.Sysse Gudrun Engberg, Copenhagen