Like others on here, I go for seats 1B or 1C (so usually 1C if booking in advance since 1B is blocked). However, I've also experienced the frustration of wanting to assign 1A/B or 1C/D when traveling with my wife. She's much shorter than me and doesn't mind the legroom in the bulkhead window. The solutions I've come up with are to either take 1C/2C or 1A/1C and hope 1B or 1D is willing to trade like for like. Of course, that's a backup to snagging the seats when they unblock at T-24 which I got used to doing for EC seats on real planes as an FO.