Backup Exec using NAS for Storage Media

Would like to replace our tape backup system with a NAS device using our existing Backup Exec 12.5 software.  Our tape system could only store about 2 weeks of backups by doing a FULL backup once a week and incremental each day.  Would like to try and expand this further with the NAS because I feel confident that it has enough storage space to keep up to 1 month of backup.  

Questions:
-  Should I do a FULL backup each week or perhaps try and push it to every 2 weeks to save space?
-  For each backup schedule, should I use a different folder on the NAS (i.e.  Folder01 for week 1 and Folder02 for week 2)
-  Does Backup Exec have a method for "incremental forever" similar to ShadowProtect where you have 1 base image and then only incrementals from that point?