Are these practice tests and books from the same thing, and if not which one is usually better?
Trust me, anything and everything is good practise. Just for practise. How you learn from what entirely depends on your abilities. Everything available is only a guide, what you comprehend is totally up to you. And make sure, after you have exhausted as much, spend at least a month or two on solving and understanding all the questions from OG. Only OG will familiarize you with the true style of the questions on the real deal. Not the quant though, quant comes not with style but sustained practise. Beware, though it is the best, it should be the last book you should seek guidance from.
I am AWESOME and it's gonna be LEGENDARY!!!