Change the default user role of new sites ( multisite ) ?

Hi good day.

I'm working on a site with 4 membership levels (WordPress Membership) and MU.

2 of these memberships can create your site to have its own URL http://site/userURL and also may have a Domain Mapping.

I need the user to create their site but its level is not an administrator

I want the user only create the site and its level is subscriber so cannot post or modify anything on the new site, I will to use the "New Blog Template" to create custom content.

Have no idea if this is possible

Can you recommend something?