The biggest problem I've always had is finding a staight base board to place the "soft" working board on. A furniture builder friend of mine told me about "MDF" which can be found at home improvement stores in various sizes. After years of frustration, including balsa building boads, I now use an MDF shelve board about 12" x 60" with a piece of ceiling tile cut to fit on it and placed back side up.The MDF is very dense and you cannot stick anything in it so you'll need the ceiling tile for a soft surface. MDF is straight as an arrow and will not twist or sag. You can put it on you work bench top and shim it to make it stable. The only thing I've found as good is glass, which is impracticle. Try MDF and a ceiling tile, I think you'll like it.