Here is a list of traditional naming patterns in Cumberland and the Border areas of Scotland.  It may be accurate for other areas as well.  Some times these things help and other times the confuse, but here it is:
 

Traditional naming patterns
 

1st son----------father's father
2nd son---------mother's father
3rd son---------father
4th son---------father's oldest brother
5th son---------father's 2nd oldest brother or
                           mother's oldest brother

1st dau----------mother's mother
2nd dau---------father's mother
3rd dau---------mother
4th dau---------mother's oldest sister
5th dau---------mother's second oldest sister or
                           father's oldest sister