Is is ok to pray the rosary using parts of psalms that I wish to memorize? My idea is to repeat the psalm on the decade beads and then an Our Father, Hail Mary, and Glory Be on each of the single beads. I do not wish to dishonor Mary or tinker with the holy rosary, it’s just that I feel so close to God when I combine the concrete bead-counting with the beautiful words, and the idea keeps popping into my head.
For private prayer, yes, such an idea is fine. The rosary beads may be used in private prayer for any prayer formula that is not antithetical to Christian doctrine and/or spirituality. In fact, the Divine Mercy chaplet is prayed on the standard rosary beads, as well, so your idea would be in line with Christian spirituality.