Looks like my screw clamps need just a bit of filing to fit fully into the Incra tracks. They go in OK but start to seize when the short leg is just about completely in o slot. My clamps are about 2 months old -- I am a relatively new Festool user, just got my track saw last month.
Peter -- a little off topic, but I got my Lee Valley order yesterday, which had 6 Parf Dogs -- 4 of the standard, and 2 of the tall. I really look forward to trying them. They fit like a glove in my homemade MFT-style workbench (3 ft. x 7 ft.), which has a CNC'd top. My reference standard for milling was the Qwas Dog, of which I have two, and they were the basis for making sure my 20mm holes were correctly sized.