Is it possible to overexpose Inkodye?

If you have a good negative it is difficult to overexpose Inkodye. It is better to err on the side of exposing your print for a longer time than avoiding overexposure. If you are noticing that the light areas of your prints are over-developing or that your print does not seem to have good contrast, you probably have a negative that is not opaque enough. Try printing two negatives and stacking them.