I think there should be a bit of play but not much. I am a bit lucky that the MoT chap that did mine was Italian (Spanish?) who owned and worked with 500s and had 126s as well, so he knew about the "play" in the front wheels. He would put the front wheel play as an advisory to cover himself and the garage. But he says, I can ignore it. Before I discovered him, I always struggled to explain how there should be some movement in the front wheels to the tester.
Difficult to gauge the tightness. The MoT chap says, making the nut too tight would mean the bearings go very quickly.
My MoT is also due in October, so I am bit anxious. I hope he still works there.