We are transitioning from Campaign Influence 1.0 to Customizable Campaign Influence.

Couple questions:

1. If the out of the box "Salesforce Model" is used and several campaigns are auto associated because the same individuals are campaign members and in the opportunity contact role, which campaign gets set up as the "Primary" campaign and gets 100%? Can this be manually changed?
2. When I enable Customizable Campaign Influence, do any of my campaign influence records from the 1.0 version get upgraded? Or are all the records for the "Salesforce Model" simply auto calculated using the auto association rules?
3. If I choose to use a new model so I can manually relate campaigns to opportunities, will I need to move all my previous relationships into the new tables?

Thanks.