Praise for Benediction:
135. That practice in a special manner is to be highly praised according to which many exercises of piety, customary among the faithful, and with benediction of the blessed sacrament. For excellent and of great benefit is that custom which makes the priest raise aloft the Bread of Angels before congregations with heads bowed down in adoration, and forming with It the sign of the cross implores the heavenly Father to deign to look upon His Son who for love of us was nailed to the cross, and for His sake and through Him who willed to be our Redeemer and our brother, be pleased to shower down heavenly favors upon those whom the immaculate blood of the Lamb has redeemed.[Cf. 1 Peter 1:19]
Mediator Dei is on the Vatican web site here. And remember, our site also examined the post-conciliar rite for Holy Communion and the Worship of the Eucharist Outside of Mass here. The Rite of Eucharistic Exposition and Benediction (REEB, though very very few Catholics refer to it as such) is in HCWEOM 93-100. If you are looking for a good post-conciliar summation of church teaching, Pope Paul VI provided it in Eucharisticum Mysterium (1967).