Well, some are obvious, like a visual - PF looks out! (As does PNF in my experience
)
AWOPS - Co looks 'in', Captain looks 'out' (with a fair bit of 'in' before
)
'Normal' coupled or non-coupled approach is down to 'choice'. I guess if your SOPs do not specify....................as long as it is briefed so each knows what they are doing.