You say nut caps? Are these plastic covers? If so these should be removed before placing socket, that’s how it reads in your post, I may be wrong. Nuts are 110Nm.
I've never personally torqued them up properly(only by feel) but now I know the number I will. Don't know what the impact guns are set at the tyre shops use but I've never had to use all my strength to get one undone.