well thats a 9t, so its way too stiff. i need to get either an 11 or 12t. so for now ill be running the standard cassette. this is just a proof of concept. also its very easy to find a 25t sprocket, so thats another reason to run smaller ratios. it also helps with crank slides.
now because the driver is so much shorter than the cassette, you have about 10mm of room between the outside bearing of the driver and the end of the hubs axle, and them you have a 5mm gap between the end of the axle and your dropout, because the standard cassettes locking mechanism has a spacer which is exactly the same dimensions as the washer you find on the hub bolt. so i took that washer, put it between the axle and the dropout, then the cut off bar is a spacer that prevents the driver from sliding around on the axle.
if that doesnt help you ill just need to take photos as its hard to explain without them. basically the 5mm thick washer is a spacer for the axle, and the cut off bar is a spacer for the driver. i also have another washer against the driver to avoid putting a side load on the bearing seal when i tighten the hub.