ElToro, I would encourage you to read up on the practice of Benediction. Having more information will help you see where your practice with the chalice fits in theologically.
Benediction is always done with great ceremony, hymns, and prayers. It is a solemn liturgical action. Whether done by a bishop, priest, or deacon, they will always, always wear a humeral veil, over the shoulders and wrapped around their hands, as they lift the monstrance. The principle is that making the sign of the cross over someone with the very Body and Blood, Soul and Divinity of Jesus Christ, is so incredibly huge, that no human being can do it, even touching only the monstrance. By covering their hands, they confess that this is not their action, but the action of God Himself. Even clergy are not worthy to do it.
(I realize that Benediction may not be on people’s radar, because I have no idea how often it happens in parishes, and many folks have never heard of it. In my parish, we do Benediction as part of the Stations of the Cross, which is every Friday in Lent plus several bonus times for those who can’t make the lunchtime practice. Also, whenever the pastor is out of town and can’t begin our weekly Adoration with Mass, the Deacon steps in with Benediction. So we have it fairly frequently and I love it and I’ve asked a zillion questions about it.)
And that, apart from any specific direction from the Holy See (though I submit to those as binding!) or anyone posting on CAF, is why a layperson should never, ever make the sign of the cross over anyone, including themselves, with either Host or chalice.