Candi, I would purchase Baltic Birch plywood. It is easy to cut and you will not get voids. I usually order the 1/8" and 1/4" and the 1/2" in 12" x 12" from Ocooch. You will find that most anything can be cut from this wood. Now, as you get more adventurous, you may want to get some maple, walnut, cherry, etc., etc. You will notice real quick that the Balic Birch is far superior to the birch you get at local hardware stores, it is well worth paying for the shipping! Now, this is just my opinion, and I have only been scrolling since March; so, there are a good many others here with more experience who can give you expert advice. Happy Scrolling!
Tony,aka,Toneman