I wouldn't consider such a trade until it is about 3-1, lead for bullets. There is a significant amount of time casting, lubing or coating & sizing. JMO.
BTW, the MC isn't really any faster, in fact slower, than using a 4-6cav mold. It does allow me to cast longer so the per hour return is about the same. I can do about 900 per hour with 4-6cav molds. The MC 2cav maxes out about 600 per hour, depending on bullet size.