Norman to answer your question, I taped the whole picture together then cut the sides and doors to size after but before I glued them to the panels. You can give yourself a little leeway on the length, but you really have to pay attention when you size the parts after the glue up. My doors were made from plywood wrapped with 3/16th solid wood with the plan to plane them down to at least 1/8th. this gave me room to shift the doors up or down as needed. Also, I did an inlay on the door sides to give the look of a continuous flow. If I do another, I will definitely plan for that door thickness in the drawing, as I didn't, I had to add to the stems and didn't get the exact look I was looking for. The photo shows the veneer before it was cut, I hope that helps.
-- Paul--- Creativity is allowing yourself to make mistakes. Art is knowing which ones to keep. — Scott Adams
