It seems like 1 or 2 F seats are released almost a year in advance, and the remaining seats are released exactly 3 weeks ahead. I found this out by searching on expertflyer. I found lots of days with 7 and 8 available O-class seats (F) for the next 20 days or so, but only 1 or 2 from thereon. Might be a coincidence, but I don't think so.
I have only been assigned isle seats on LX F redemptions, but I have called and requested window seats, which worked fine.