Jackdaw Express Tissue Box Cover - Self Assembly White Cardboard x 5, Choose Rectangle or Square (Square)

First time buying this. Firstly the size, whilst probably fine originally is no longer compatible with the tissue boxes on sale just now. These have been reducing in size so this box cover is too deep. Length and breadth is fine so I cut it to size but my first attempt at decoupage on it was not great. The cardboard seems a bit thin and didn't keep its shape. Went wrinkly just with diluted PVA glue. I will practice on the remaining ones, perhaps using only as a stiffener for a fabric cover.