It can be as complicated or as simple as you need to make it.
We use weld mapping and tracking separate from our welder logs. Our welder logs are used primarily for maintaining welder continuity and to assist with HR functions. A separate log helps rod room attendants verify that the welder has the necessary qualifications to have the requested filler issued to him/her.
If you can better define what the customer is looking for, we can probably offer something a bit more insightful.
Some question to ask: is NDE involved at all? Are your welders assigned stencil numbers? Are they assigned employee ID numbers? Are they qualified on different materials with different fillers? Are field weld numbers assigned to your weld joints, or is the welding primarily structural? etc.