These repetition methods are meant to take the place of speed bench on dynamic effort days. Louie encourages those whom do it to stay at a double illegal (2 finger widths past the power bar's ring) grip throughout. This is typically run with no accommodating resistance, and either with a straight bar, bow bar, or cambered bar.
For the 6x6, he recommends starting at ~70% 1RM running it in a 3 week wave and adding 3-4% each week.
For the 8x8, start at ~65% 1RM.
And for the 10x10, starting at ~60%.
The idea of this training is NOT to fail, but to build volume with the repetition method.