Here's an interesting article.
https://www.headforpoints.com/2021/0...ard-flights-2/
Unfortunately F seats are a rarity now especially with the downsizing of cabins, the demise of the 747's as well as quite a few aircraft are now only 3 class so the West coast CW ones are snapped up extremely quickly too.
Some BA FTr's report seatspy is quite good and you could set an alert on EF but otherwise its usually fastest finger/calling at the exact moment when they re available.
The good thing with alerts is that if you miss them then there's always the small possibility more are released. Travelling off peak might help, slightly but for this summer i wouldn't be optimistic of getting any CW seats but you never know!
Pete