Hopefully easy question: speaker cable spade size

Hi I'm a new member in the process of assembling a 90's Levinson system using a 23.5 amp.  I'm selecting speaker cable and I'm supposed to choose either 6mm or 8mm spades.  I don't have the amp yet to measure myself and searches on google and this forum haven't answered the question.  If someone knows that will help a lot so I can place this cable order.