I never heard tell of a Crown Graphite, is it similar to a Crown Graphic?
Now go to the hobby store and get a piece of Baltic Birch Plywood, 1/4 inch thick.
Cut a blank that fits the outside opening then round the corners so that it just sits into the board opening.
Remove the focus panel or back.
With the board blank in the front standard mark the bellows throat outer edges on the back side of the blank.
Cut the area outside of the bellows throat marking down to 1/8 to 3/32 inch thick.
You will know you have it correct when it just sits into the front standard and the board locks just slide over it with no gaps.
Cut the hole for the shutter then recess the mount ring as needed to reach the shutter and tighten at least 3 turns.
Stain or paint flat black on the back side and finish to taste for the front. Stain works better as paint adds thickness and can change a close fit to a no fit.
Been there, done that on 4x5 Pacemaker Speed/Super Graphic.