Self-study with MGMAT and do a course with VeritasPrep?

Hello,

I am just starting my self-study plan but I have a question about books. I have read that the MGMAT foundations books are great in combination with the OG (I need a desperate refresher on math). I am not planning on taking the GMAT until next summer as a I have the JLPT to take in December. Between now and December I was going to do self study with the MGMAT books and then take a Veritas Prep course. The Veritas Prep has the best times for me because I live in Japan, but I don't want to buy their set of books if I am going to get them through the purchase of the course.

Is it alright to use a few different company's books or would it become confusing or a waste of money? And should I get the full MGMAT series (8 books) for self study until I start the Veritas Course sometime in January/February? I was looking more for a refresher of foundations and basics, and using the course to get into the details of what I will need to know.

My goal is to get a 680 or higher and enter a grad school in Tokyo or Kyoto in fall of 2015. Any advice would be greatly appreciated.