I think a hybrid 4 perm is the best for everyone. So at a minimum you play everyone every 3 years.
For example
UNC- would have Duke, NC State, UVA, Wake
FSU- would have Miami, Clemson, Cuse/BC, GA Tech/Louisville
So UNC plays those 4 teams yearly and everyone else once every three years. FSU plays Miami and Clemson yearly, SU/BC/GT/Louisville 2x in three years, and everyone else once in three years. So they get their Northeastern game 2x in 3 years but more variety. They also get GA Tech more often. So they have 4 "perms" but the perms are regions and not individual schools.