Best way to permission Server 2008 R2 File Server

I am migrating an old file share to a new domain, It used to be on it’s own File Server, Migrating the data to an RODC and the small file share will be located on it. I am going to re-permission the folders from the group up. In the past I have found it easier to add Domain local groups to the folders as below, and AD users to global groups, and add those global groups to the DL groups. I find it easier to manage this way, does anyone else know a better way, or can you tell me the perks of this way or other way(IE: just adding global groups to the folders??

Folder A> “PERM-DL-FOLDER_A-R”(Read group), “PERM-DL-FOLDER_A-M”(Modify group)
Folder A1> “PERM-DL-FOLDER_A1-R”(Read group), “PERM-DL-FOLDER_A1-M”(Modify group)
Etc.

Accounting> PERM-ACCOUNTING Add to PERM-DL-FOLDER_A-R and PERM-DL-FOLDER_A1-M
Testers> PERM-TESTERS Add to PERM-DL-FOLDER_A-M

Thoughts?

Thank you for your assistance.