The light classes are growing every year in my area too. We also start at 2500# and run USAP rules with multiple speeds. Most folks are building light pullers now because they are much easier to haul, less weight to move and you get to pull early in the order. The 3500-4500# classes have really heated up in the past few years. The number of tractors in each class starts to thin out pretty quick past 6000#. We have heavy classes too, even up to 12,000# but very, very few tractors and dwindling more every year. At our spring pull there were no entries above 9000#.