I believe you are in a dilemma here between CUG and Provide Access control using CRX.
1. CUG: It is Closed User Group which is clubs the different user to share same permission. When a CUG (Group Permission) is applied to any content/page, all the users who are part of group will have same permission to those content/page.
2. CRX explorer Permission: It is generally to explore/see and edit permission for individual contents/pages in special cases.
Though you can give permission using CRX however its not at all recommended to do so. Always create a group of user (even it has one user initially) and give permission to group. This is because if some more users may join in future or may leave hence group will be constant. Never ever give individual user permissions (not recommended by Adobe).
Hope This helps 