Can I increase the size of link arrowheads and repression feet?
If you are having trouble distinguishing the signs of the links, you can increase the size of the repression link “feet”; the arrowhead size is currently fixed. The larger foot size is global, and cannot be modified on a per-link basis. Note that if you increase the size of the repression feet, you will have to manually make sure the spacing between incoming links into a target is large enough to keep the link ends from overlapping.