Cebo, I think you will find every girl will be different on every week of every month. There is no rhyme or reason as to when guys call or make bookings (bar between 22 and 28 of each month when it is usually quieter).
Every month is different too and it also depends on school holidays that month too. So Scotland, England, Ireland and Wales are all different.
It is a case of trial and error and even then there is no way of knowing if you are busy this time this week that you will be busy same time next week.
The long and the short of it is, there just isnt an answer to your question which has been asked a million and one times already.