That sounds good Jennifer - I am the same. Have been charting for years and you get to know what your body does. My mucus starts to change from thick and opaque to thinner and clearer 5 days before O, so even if my ovulation comes earlier or later, the amount of days with fertile mucus prior to O stays the same, which makes it easy to guage. The other potential tip or sign for me is that my 'O' pains hit a peak (become most prominent) the night before my first high temp. They are mildly present when the change in mucus occurs 5 days before O, but become gradually stronger and reach a peak right before the first temp spike so that pretty much confirms for me that ovulation is occuring close to the time when my O pain is at its strongest. If I wanted to conceive a boy (already have 2 so won't be doing it next time) I would just be able to run to the bedroom on the evening of the 5th day of fertile mucus, when O pains are at their peak. Its hard for me to avoid having boys because I get so errmmm - 'in the mood' shall we say, around ovulation!! he he. Plus your cervical mucus becomes more alkaline the closer you get to O so that favours a boy conception.
I will have to restrain myself next time we TTC and go with the 3 days prior to O method....... sigh.