Hi Bussy, and welcome to Outdoorking.
Please take pictures as you assemble the center of your Greenfield clutch and adjust the clearances, as well as writing an explanation of how you do it. Note aldot reported that it took him three tries to get the right shim thickness to achieve a clutch clearance that worked well. If you measure the clearances (both disks to both friction liners) at each attempt, you can tell us what clearances are needed, so in future people will read this thread and won't need three tries.