Unfortunately, I think this is over complicating what I'm trying to accomplish.

My goal really is just to set up each client the same:
-Image-based
-Backup all partitions
-Enable compression
-Synthetic full backup
-Recurring schedule
-Full backup: occurs every 1 month on first Sunday at 01:00
-Block-level Incremental backup: occurs every 1 day at 18:00

I'm so used to GFS and I'm struggling to understand what my retention policy should be when utilizing Synthetic Fulls. Say I want to keep 1 month. Do I do this for instance?:

-Specify custom retention policy for plan
-Keep number of versions: 1

or do I do:

-Delete versions older than 1 month

And do I or do I not check 'Always keep the last version'?

What would be the best method for a one month retention?

Role of the servers are typically just Domain Controllers/File Servers. A couple are running SQL. We always do two volumes, one being system only and the other for data. Applications would be located on the data volume. No legal requirements must be met. For the synth full we would be doing image-based and all partitions.