I think this is one of those where there's not necessarily one 100% correct answer, as there are multiple ways you could do it all of which have their good and bad points.
In terms of labelling the tapes, I think the most important thing is to ensure that however you label the tapes you can easily determine which ones are required when, and when each tape was used. From your description, if we assume the full will be done on Fridays with four weeks worth of tapes, and incrementals on Monday to Thursday being reused each week, I'd probably go for something like :
Monday, Tuesday, Wednesday, Thursday, Friday 1, Friday 2, Friday 3, Friday 4.
You then know which day of the week needs to go in, and just need to keep track of which week you are on. If you added a 5th friday tape you could then go with the 1st friday of the month, through to the 5th friday of the month where required.
I think the most important thing is to ensure that you have the physical labels on the tapes corresponding to the tapes in the drive, so if you need to look through the log to find out what happened you know which tape it is referring to. There's nothing worse than looking in the log and seeing 4MM000001, and having no idea which tape that actually is.
Backup Exec doesn't really care about the tape rotation you choose, and uses the media set information to decide if it is allowed to overwrite the provided tape. Since you specify the media set to use as part of the backup job, creating just one media set and one backup job will mean that your friday tapes will not be protected properly.
I'd suggest creating two media sets, one for your weekday tapes, with 5 day overwrite protection and 1 day append, and a second media set for your friday tapes, with 3.5 weeks overwrite protection and 1 day append.
