I agree with Greencat's suggestion about how to dress. I think small earrings in all 4 holes would be OK, but if you are doubtful (after all, you know where you have applied!) leave the upper ones empty and wear small earrings in the lobes.
So far as hoops are concerned - I would not see larger hoops as being over the top, but I tend not to associate them (especially if they are more than about 1/2" in diameter) with professional women. So as an employer, if you came to an interview wearing large hoops my first impression wouldn't be as good as if you were wearing something smaller, or more discrete. Where I live (In the UK, in a fairly rural, small-c conservative area) large hoops are not common office-wear, so if someone turned up for an interview for an office -based job the 1st impression would be slightly 'off'.
It wouldn't stop you getting the job if you were the best candidate, but there would be that subtle, slightly negative 1st impression.
In terms of work place, if you were interviewing for a job as a bartender or similar it wouldn't have the same effect.