I have several solutions. The last one is a modified belt sander with a larger belt and a wheel with a ball bearing. But the belt moves (up/down) during sanding.
The best solution i own is a jet spindle sander. I (let) made an inlay with an edge on it. So i have an offset to the contour but this works fine. I am already searching for a solution with an edgesander but will not invest in a new edgesander.
Search on youtube for the alberty archery videos.