Hi Matt,
Shipper made a post a few months ago about the adfmentors OSB course, definitely worth checking out. I recently took their course after reading their material and seeing a few other people talk about them on here and it was fantastic. It definitely boosted me to the next level of preparation, they conducted a number of mock OSB interviews/exercises and really taught me to answer well under pressure. If you google them it should come up.
Ranopaul