To add to Scott's answer
for Mon-Wed use a media set with a 6 day OPP (Overwrite Protection Period)
if you want THU and FRI on the same tape, you need to either make the FRI job Append, or run the same job THU and FRI, defined as Append, else Overwrite with a different media set and OPP
I'd probably go with two jobs, THU as Overwrite and FRI as append to the same media set