Step 3: Scale Template down, Trace Main Body, Cut out on Band Saw
Before securing the four rough pieces with wood screws, throw some glue down where the heart will remain when cut out because you want the body to be a solid piece. I even put 3-4 screws along the heart outline, 1/4" from edge, spread out according to the image. This ensured that once the main body was cut out and a compartment cut out of the center in later steps the four layers would stay intact.
****Size of the wood screws depends on the depth of your layers, should be enough to secure each layer but not puncture bottom face. Otherwise it will not slide well on the Band Saw table, nor mesh with the bottom plate either. I used 2 1/2" screws.
My heart box body was made up of 4 layers which was roughly 3". You could choose to add layers in order to create a larger compartment, you're only limited by the size of your band saw. Space between the guard and table is the limiting factor.