If I remember correctly Thursday was the big one if you've got enough connections to buy and rate. Saturday was an easy one too but rarely gives you enough momentum to stay on the list into the following week.

Take all of this with a grain of salt, we talked about it over drinks so my memory is hazy. I just checked his site and he doesn't mention the service. I think it was a word of mouth thing (maybe because of Amazon ToS?).

Looks like # of sales/hr on that first day is one of the biggest factor (plus Kindle purchases vs paper): https://scribemedia.com/how-to-become-amazon-bestseller/

^not my friend I just got curious