Sleeping bag liner or full sheets?

Hi I%26#39;m spending one night in Copenhagen soon and plan on staying in a hostel. Do I need to take a full set of sheets with me (top and bottom sheet plus pillowcase) or is a silk sleeping bag liner (plus separate pillowcase) enough?

Want to avoid linen charge as only one night and don%26#39;t want to carry around a set of sheets if I can avoid it!

Also is there any real difference between DanHostel City or downtown - locations and reviews I%26#39;ve found are fairly similar (i.e. ok not great!. Any better recommendations welcome)

Thanks