I prefer Row 7 to Row 8 for a number of reasons that have already been covered - smaller cabin, more private and less commoners () traipsing through once you're sat down (unless you like looking smug as they trundle past - which sometimes I do). Plus if you do enter from 2L like everyone else, you get the pleasure(?) of turning left. I've also never had an issue with leg room in Row 7.

I'd also say yes to upgrading J to F for a 6hr day flight - again for reasons covered above. Though you only benefit from the DXB F lounge if you're departing from DXB (i.e. not on the incoming flight)