Mafia: general discussions.

Hey everyone, I'm curious to hear your thoughts on something. I was working on a scenario and ended up creating more roles for the Mafia than they actually need. Should I include all of them in the scenario, and let the Mafia players choose their specific roles? In other words, I could create 6 Mafia roles, but only 4 need to be selected. One or two will definitely end up on the team, and the other two will be chosen from the remaining options. Players would receive their Mafia numbers, gather together, and form their own team, possibly even assigning roles themselves, although I could also handle that. What do you think?