your funnel problem, how did you solve it?
do you think if you had a V design ( think of the inside of a V-hull boat) it would create a little less flat surface friction on the edges of 2 coins trying to go into the opening right before the comparator at the same time? the only thing I can see with that would be changing the opening to the comparator to accommodate the angle, or a flat "slide" just past the opening- which would mean more distance between the sorter funnel and the comparator