When you mentioned that today it ran 'almost too dry' was that because you didn't like the color of the skimmate, or because nothing was collecting initially?
It almost sounds like you're trying to produce a specific product in the collection cup, and you adjusted settings to make it happen. It could be that you're running it too wet overall - as in, you start it up, and it takes a while to build back up a frothy head, and at that point you get an overflow. For a while at Premium we had an older BK and a newly-released cone running side-by-side on a coral system. They didn't produce the same skimmate, even though they sat in the same depth, in the same sump, in identical water. Maybe you're just aiming for an ideal that doesn't work in your system...
Try this: Adjust the entire setup to run dryer than you have. While you may not see immediate collection of a large quantity of tea-colored skimmate, that's not really the point of skimming. Skimming removes a set amount of organic matter from your water column. A slower-filling, darker-colored, dryer skimmate is just as effectively removing those compounds from your system, just without sacrificing any extra system water.