I am seriously thinking of taking my first ever intercontinental flight either this summer or not long after, AF BHX to CAN. Biz fares seem to cost about 10x the price of the cheapest Tempo ticket (which BTW is quite affordable at under £400 inclusive of taxes) and I can't upgrade on AF for my OK miles. One of the OK+ silver benefits is "preferred seating" on all longhaul Skyteam flights.
Does this mean that I am likely to be able to actually reserve the seat I desire on booking or is it a checkin only option? Or is it just about preference of window over aisle and v.v?