There are huge differences between a Missa Cantata and a Pontifical Solemn High Mass. In addition to the sacred ministers and servers needed for a Solemn Mass in the EF, there are two deacons of honor at the throne, and each has very precise tasks, such as who puts on the gloves (both do), the pontifical bushkins, the gremiale, etc. There is also an archpriest in cope, who has very specific duties, some of which are normally the subdeacon’s and some that are normally the MC’s. There is a second MC, and four attendants to the bishop (carry the bugia, crozier, mitre and pontifical canon). There are special rituals for the entrance of the bishop, and his vesting in the sanctuary. There are two different mitres used in the course of the Mass, and the Blessed Sacrament is normally removed from the tabernacle before the start of Mass. Much of the Mass is conducted from the pontifical throne, rather than at the altar. The bishop processes ceremonially from throne to altar, and back. There are many people involved in the sanctuary–much more complex than even a Solemn Mass, let alone a Missa Cantata.