Size 14 & 16 plastic KAM snaps have the identical sockets and studs. Only the caps are different. For that reason, the same socket & stud dies can be used for both sizes and only a different cap die is needed is using the professional-grade dies.
What to buy for professional-grade dies:
For no-change dies, the same die set can be used for both sizes but results may not be as precise or uniform compared to the professional-grade dies.
Learn more about the differences between professional-grade and no-change dies.