I can't see an option to createa new Media Set every 4 weeks, In the Automatically Create New Media Set (Daily) I have the option Everyday or On These Days - with a choice of specific days of the week.
Just as a test, I changed the Data Retention Policy for the exisitng tape I've been using for Incremental backups (with a media set created last Monday) and ran the job.
I was hoping that a new Media Set would be created for this job (as the Media Set rule is to create a new Media Set each Monday, but that the media set from last week would not be overwritten since the data retention policy was set.
Unfortunately the job now wants a tape to be added, as I guess it won't use the current tape with the Data Retention Policy of 4 weeks.
On your last point about synchronization of Full and Incremental Media Sets, I'd like to use somthing along the lines of the following.
Full backup every Friday night using a rotating pool of 6 tapes and a periodic archive:
Week 1, Week 2, Week 3, Month 1, Week 1, Week 2, Week 3, Month 2, Week 1, Week 2, Week 3, Month 3, Week 1, Week 2, Week 3, Archive
The Weekly and Monthly tapes would be re-used as required and the Archive tapes never re-used. The Weekly and Monthly Full Backup jobs would give enough restore options, especically if we could have the incremental jobs backing up the changes during the week. We used to run a Full backup job every night using Backup Exec, but as you can imagine, that was a waste of time and tapes as hardly any files changed night on night. It did give us the easiest of restore options though as we only ever needed 1 tape to restore anything.