Regarding F, I tend toward 1C or 1D, although it is a bit annoying to have to put my "underseat" bag overhead.
Regarding Y, one other nice thing about 23F is that it's much easier to get to the aisle. You don't climb over the pax in 23 D/E, you go forward and past 22 D/E, who have enough legroom that they barely have to pull in their feet. And 23F has underseat storage under 21F (not true of 23A because of the crew jumpseat). 23F, interestingly, is not MCE but "preferred." So you can't buy it, but it's free for all elites. You don't get free drinks like MCE does, but I rarely drink liquor anyway.