Question about a Dozen

I wondering if someone has the stats for the average hit ratio for one sleeping dozen.

For example, Lee Tutor says wait for two dozen to hit seven times then bet the sleeping dozen five times and you have a 99% probability.

But I also remember reading that the average is two dozen hitting five times in a row and then start betting the sleeping dozen.

I would like to read the classical methods based on this methodology and see what others say.

If you have such a system or can give me a link I would be very grateful.

Many thanks, Patrik From Sweden