the 5/3/1 programme itself is a ‘strength’ programme and not a mix of all methods, aka westside style. if you are doing something different then it is not the 5/3/1 programme.
The programme itself requires you to use 90% of a 1RM as the training weight to be used in the programme.
I have read the book and use it’s methods with about 8 of my players at the moment, i usually follow it for 2/3 cycles then we shift the aims to something different. This also depends on weekly in-season demands, such as how many times we can lift that week etc.
I highly recommend that you purchase the ebook from elite, its not that expensive and it answers many of the questions most people are asking about it.