I am making a wedding cake and using SPS for the first time.  I just realized my 6 inch SPS plate is going to show on my 6 inch hexagon top tier. I have googled and read to do this.  My plate is going to show some.  Do I just frost edges of plate with BC & smooth to cover?  Are you suppose to use a smaller SPS plate for hexagon cakes?  Detail of cake below if needed.

12 inch hexagon bottom tier, 8 inch round tier and 6 inch hexagon tier. (On a 14 inch foam board).  Torted & filled, all BC.

Thank you so much!