Names on place cards

Just wondered what people are putting/put on their place cards. I didn't really want full names as it is quite an informal do, however we have a couple of people with the same name. If I put first names only do I assume that they will know who they are because of the people sat near them, or should I put full names on the seating plan and only first names on the table?

We're putting full names on the table plan and then first names on the place settings, although we will put the first initial of the surname where we have two people with the same name both sitting on the same table.

Our place cards were written as I'd call my guest (eg Aunty X or Nan etc) but for people with the same names, we put the last name on the seating plan and not on the place card. I wanted it to be informal too.

I'm putting mostly first names (some nicknames), then for those with same names, first name and last initial, and for those with same names and last initials, first name last name.

We'll probably just do full name on seating plan and first names on place cards