I have a similar potential option on a flight to DOH later in the Summer. When I booked it, it was 77W so went 5A. It then changed to 77M (4-class) so no seat change but about a month out it often changes to 77L (3-class) which opens up rows 1-4. My approach was to stick with 5A in case of any change back to a 4-class aircraft and from experience mid-cabin avoids the 2 x toilets and galley at the front. Also assuming that they use door 2L you're off pretty quick from 5A.