How Long To Move To Engagement+? To Get New SKUs

Hi there, we have been using Marketing Cloud Engagement for a while. We are keen to move to Marketing Cloud Engagement+ so we can start using Marketing Cloud Next functionality. Our SF Sales reps have suggested for a while that we should use Engagement+, and have said that we will need the new SKUs added to our contract, however, it is taking a very long time to identify the SKUs to add to the contract. 

Has anyone gained access to Engagement+ yet? How long did it take? Do you know which SKUs were involved for Engagement+? Is there n extra charge for gaining access to Engagement+, or is it really just and upgrade? 

FYI We have been using Data Cloud for 18+ months, so we are confident with DC360.