What to do when a media set is full

[SabKay_95]

Hi,

I've got a backup set that has 2.7Tb but the tape size is only 2.3TB. Causes the full backup unable to complete because of over the limit size of the tape. This backup set has a setting to backup to this 2.3TB media tape every friday and the overwrite policy is 5 days and append is 1 day. 
Would it help to just reduce the overwrite policy days?

[Gurvinder]

whats the compression ratio you achive with this backup ? Do you start from start on this tape every week ?

[kf2013]

How many tapes are in the media set?

Do you enable compression?