Problem is there is more to timing than just timing of BD and O. If you read some of the swaying info (including Shettles) they will tell you that if you want to conceive a boy the Man must not abstain for no more than four days before your 'attempt'... at which point Y sperm begin to die. However there is also some stats saying that abstaining for more than four weeks (I think, don't hold me too it) that more boys are conceived.

Another thing to think about is that LOTS of boys (can't remember the %, but in comparison to girls on a full moon it is a VERY high % rate) are conceived on a full moon

There is more info on this but I can't remember it off the top of my head.

ETA:
DD#1 no idea
DD#2 no idea (LOL... however I had just come off the pill and aparently the pill make the womans internal environment more acidic )
DD#3 3 days before O
DD#4 DTD day of O