I think it ought to start with extraordinary eucharistic ministers. There should be a formation period and catechesis so these laymen are taught what it is they are handling. After this, it's time to move on to the rest of the laity.
For goodness sake, we are distributing, receiving and consuming none other than Christ Himself! This is the second Person of the Trinity! This is God! If there is even on Catholic who does not believe this, then we have failed that person.