727/46re geartrain endplay to tight

I believe thats what it is called. You assemble the planets on the shaft with all the thrust washers, and install the C-clip. Flip it all over and have the sun shell on the table, and then you put a feeler gauge between the very bottom sun gear and ensure there is proper play.

Well I can't even get the C-clip on! I have the smallest C-clip that is available as well. All the thrust washers are new. Am I overlooking something perhaps? Any tricks? tips?