“I was just careful when I made the dados on the aprons and they were TIGHT!”
?!? One of the interesting features of the Paul Sellers workbench is the use of wedges. They can compensate the possible shrinking of the legs and avoid subsequent raking.
By the way, for the correct working of the wedges, the leg frame must be able to move a little bit (left-right). To allow for this, the hole in the leg frame for the carriage bolt must be a little bit larger then the bolt diameter.