Because you are only embossing, it is acceptable to place one die rough-side up and the other die rough-side down.
This placement will create a large inside edge:
(A plate, B plate, dies, your card, 3 sheets of cardstock, tan embossing mat, B plate)
 Large inside edge:
 Large inside edge: This placement will create a large outside edge:
 This placement will create a large outside edge:(A plate, B plate, dies, your card, 3 sheets cardstock, tan embossing mat, B plate)
 Large outside edge:
 Large outside edge: Circles are fabulous for this technique also.
 Circles are fabulous for this technique also. 
 
