As far as I know, a proper genuflection, as has always been taught to seminarians, for example, is made in a dignified way, i.e. not rushed, but not staying down on one knee, and with a straight back and head erect, looking at the tabernacle, and without making a sign of the cross.
But why are they getting didactic about it? People can add their own devotions if they like. One good custom I know, if it doesn't get in the way of anyone else, is, after genuflecting, to stay facing the tabernacle and say a short mental prayer, such as: "My Jesus, I believe Thou art truly here present in the most Holy Sacrament of Thy Love."
I always think it's better to genuflect immediately after entering the church, to acknowledge Our Lord first, rather than just before entering a pew, but that's just my idea!