Hi Richard,
The end float is not affected by the thickness of the sprocket. The shims go onto the crankshaft just behind the large thrust washer. So end float is achieved by moving the thrust washer away from the bearing cap. So the shims should be no larger in diameter than the main beaing journal so that they can fill the “void”. Does this make sense. If you are still unsure I am happy to talk on the phone 07899 658634.
p.s. Best practice says that the sprocket and thrust washer should be nipped up before the final torqued tightening of the main bearing cap, this will ensure it is tightened with both upper and lower halves in contact with the thrust washer.
Good luck Philippe.