I have an Adirondack chair project in progress, and I bought all the lumber in clear western red cedar.  My problem is that the seat bottom and back slats were designed as full 3/4″ thick “1x” lumber.  What I got, and I paid a fortune for it, is 5/8″ thick, a full 16% thinner.  To use this stuff I will need to modify the design, adding an eighth here or subtracting it there, but I am bummed that the slats will deflect more under load and the overall look, since the back slats are such a key feature, will be lessened with the thinner boards.  Is this 5/8″ thickness what all the mills are shipping now?  I am in the northeast, and probably all that comes in is from the Canadian west.  I cut and finished all the parts made from 1-1/2″ and 5/4 stock, but have not touched these so-called 1x boards yet.