This is a less exact thing than you're thinking of it. The whole point is just regular BD to ensure that you are covered with an attempt. How you define e4d is a little bit up to you and what you really want from your sway. Closer attempts MAY be more blue friendly but higher odds conception, further attempts MAY be more pink friendly but lower odds of conception. SO, you need to ask yourself which element is more important to you and go with that.

Most people are doing e4d with Wed/Sat timing.

BUT, depending on what you want, you may change that up.

Some people might want to attempt on Friday (this would really be more like e3d) for a better chance of conception. Others might want to stretch to Sun or even Mon. for higher chance of pink. It's your sway so you need to decide what you want from it this month.