at McKinsey they will always provide paper, and normally also collect your notes.
As for how optimize notes, my recommendation would be to keep the paper horizontal and divide it in 4 areas as reported below; when talking notes, you can then put the information in the appropriate box. Sometimes you would have to do back and forth, as you may get information, objective 1, additional information, objective 2, etc.
The areas on the left and on the top should be smaller to leave more space for the structure:
- top-left: who is the client
- bottom left: initial information
- top right: objectives
- bottom right: structure
After the first page, you could still divide the page in four parts. Left and right could now be at the same distance. Top areas should be smaller to leave more space for the structures:
- top-left: name of the first area analysed
- bottom left: structure for the first area
- top right: name of the second area analysed
- bottom right: structure for the second area
Hope this helps,