Membership OR Pro-Sites or Membership AND Pro-Sites

I have asked the community here [https://premium.wpmudev.org/forums/topic/membership-or-pro-sites-or-membership-and-pro-sites] but so far the community seems to gone back to sleep.

To be able to offer a different number of blogs at each level it seems my only choice is a combination of both Membership Pro AND Pro-Sites.

My preference would be, if possible, to be able to implement Pro-Sites without having to implement Membership.

Within Pro-Sites there is also the ability on the back-end to allow users to upgrade multiple sites at a lower cost by purchasing Pro Site credits. With the way it works at the moment, after purchasing credits they have to come back to a Pro-Sites page, search for your sites via the tool at the bottom of the page, and upgrade them to Pro Site status. Each site is upgraded for one year.

It seems like a really clunky of doing it. My goal is to allow all users to buy more sites than they already have, as smoothly as possible, without this two step process. The ideal would be to allow users to sign up for more than one site at the beginning.

How can I do this?

Terence.