Symantec recommend that frequency & calendar based schedules are not mixed in a policy - but we do & have not had any scheduling issues.
We have daily frequency based incrementals & monthly calendar based fulls.
If you have any concern over which one is likely to run, set your monthly full backup window to start a few minutes earlier than your frequency based fulls.
There are some T/Ns or other docs out there that may clarify this, but I can't find them at the mo - will post them if I find them!
***EDIT***
Additionally you could exclude the dates that the monthly saves run from the daily schedules - altho' this can be a bit of a pain.