I am making up some Oak shelves for a book case. I have to make up each shelf from 3 boards 2 are 3" wide and one 2" wide. I have planned each face and edges however each board is a different thickness. Should I thickness each board before glueing or should I glue up then thickness the completed board?. I have a thicknesser and I intend to join with no 10 biscuits.