Hey Judy, Why not be the Guinea Pig? try them out and report back on them!
As for me, I used to use double backed tape, but I found it difficult to separate the layers. I now use two methods. If the stack is a portrait where the outside edge is part of the project, I use blue painters tape on the outside edge only. If the project is being cut out from inside the stack, I use a hot glue gun to glue the edges of the stack. Its actually a lot cheaper than using tape, but holds a lot better.