Started out with some simple clamps. I should clean them up a bit but they work.
The other part is a guide that is parallel to the x-axis. It has a cleat on the bottom that I put up against the edge of the spoil board and fasten it down. The other side has been faced so it is exactly parallel to the x-axis. I can set a piece of stock against it or use a spacer that I know has parallel sides to offset my stock. Generally I should not need to remove it so it should stay parallel. I'll make a second one that does not have the cleat on the bottom that I can fasten down along the y-axis to create a square registration for repeat milling.