Instead of glue, experiment with mixing sawdust with cooked white rice as a filler. The rice dries rock hard and will take stain the same as wood.Wonderful craftsmanship. A real eye opener!
I have a question Paul - If you decide to use sanding dust and glue to mask gaps, how do you prevent the mixture being a much darker and more saturated version of the wood colour? I have always found this a problem and never found a solution.