Is grace quantifiable? (Catholic understanding)

As stated into the Catechism > **CCC 1996:** Our justification comes from the grace of God. Grace is favor, the free and undeserved help that God gives us to respond to his call to become children of God, adoptive sons, partakers of the divine nature and of eternal life. and also > **CCC 1997:** Grace is a participation in the life of God. It introduces us into the intimacy of Trinitarian life: by Baptism the Christian participates in the grace of Christ, the Head of his Body. As an "adopted son" he can henceforth call God "Father," in union with the only Son. He receives the life of the Spirit who breathes charity into him and who forms the Church. Grace is the action of God, through the Holy Spirit, of sanctifying the soul, i.e. transforming it to be in conformitiy with God. Thus, my question is how can we talk about God disposing greater graces to some or lesser graces to others? And if its only a "matter of language", how can we talk about some saints being greater or lesser than others, e.g. The Blessed Virgin Mary being the Most Holy and greatest of all saints?