I do think the best shot at a boy is with lots of natural EWCM BUT Preseed can only help.
I typically have people try for 3-5 attempts in the fertile window O-3 thru O day. Most people want to avoid O-2 and O-3 because they think it is Shettles timing that sways pink (it doesn't) so if you don't want to have attempts those days, 3 attempts starting at pos OPK are great. Have one the night of pos OPK, one the next morning if at all possible, then again the next night (will be O day).

