Network Enable, or Level 1 Enable in Pro Sites?

Hey folks, me again with another question for ya.

I've got Pro Sites installed for my multisite network, and I want to know which is the better option for "performance" on my site. Mainly, I'm wondering about the database size, or Wordpress's interaction with it.

Is it better (speed and performance wise) to "Network Enable" themes that I want everyone to be able to access when they make an account, or to deactivate everything at the network level, and set these 'everyone can use' themes to the lowest Pro Site level in the "Premium Themes" tab? I know Wordpress is a platform that, with less enabled, better performance happens. This is true with plugins, but how does this work with this particular situation?

I have "Pay to Blog" turned on, so there are 3 paid levels.

Does this even make a difference? Thanks

- Charlie