100% with JT there.
The problem with the autothrottle approach is that as JT says, it (Boeing, anyway) adjusts for wind effect by flying above 'bug', but what people are not aware of is that when you disconnect the a/t, the bug setting is then incorrect as it does not have the 'extra' margin. It should then be adjusted to the target Vref or you finish-up 'ignoring' it which is not the taught technique. Winding the bug up to target with a/t engaged merely has the a/t fly even faster!
As JT says, there is no easy answer to what to bug. Each case is different. EG R26 LGW with a south-westerly gusting wind finds me keeping the excess on till quite late!