Shettles method for a girl

Hubby and I would love a girl (we have 3 boys). We thought we would try the shettles method (because why not). I am due to ovulate on the 1st. Those whom have done the shettles method to concieve a girl in the past

...what day would you stop having sex on?

I know this isn't scientifically proven....so please dont bother to comment if you have something negative to say or passing judgement.