Hi @adnw
Either way is acceptable. There is an added bonus with setting up the Affinity Account first which is that you don’t need to have a unique email address for all of the accounts.
The Power User Subscription is a different feature from the Affinity Account. Each of these have their own pro’s and con’s. For more information on the differences, please check out the following link: Power User Subscription vs Affinity
This really depends on whether you think that having an Affinity Account would make things easier for you to manage your multiple businesses or not.