A plywood backing board would help a lot. One thing is as you do more, you learn how to hide breaks and mistakes. For the most part, if you don't point it out, no one will ever know. But where long term stability is a concern, think about the material you're using. While regular wood looks great, they can be more fragile due to the grain patterns and directions. Most scrollers use thin plywoods, seems like Baltic birch is a favorite, for delicate fretwork because it's more stable than most natural woods.