[Chris is me]

Jake,
One other thing I'd look into with regards to turning scrub problems would be how rigid your frame is diagonally (cross-corner). A less rigid frame is more likely to flex just a little bit and result in the outer wheels touching the ground when they shouldn't, leading to the problem you described. From what I've seen of your frame this year, it really shouldn't be an issue, but I've seen it happen to a few teams. I think this is part of why the Kitbot has a larger drop than average - the frame is less rigid than a more solid welded frame.

You may be able to avoid the dynamic turning compliance problem with wider Colsons. I noticed at IRI that your drive base was running very thin (7/8") Colsons - experimenting with 1.5 inch wide Colsons, while it will add some weight, could help a bit too. Since the weight of the robot is distributed across more tread, there should be less localized pressure on the tread and thus you might get a bit more freedom turning. I know this sounds counterintuitive, but we've had great results with the wider Colsons and I thought I'd just throw in another data point to test.