Through browsing and reading various blogs and websites, I came across a simple and easy tip for storing 2 box stamps sets like the ORNAMENT KEEPSAKES (#128051) set in the holiday mini.
Slide the (2 of 2) cover sheet in the sleeve on the back of the case first case (1 of 2) and place all rubber cling stamps inside the case. COMBINE THEM! I told you it was simple. I nearly slapped my forehead and shouted "why didn't I think of that?"