I use both. If I get a question right, I will use the written explanations only if I want more clarification. If I get a question wrong, however, I will read all the written explanations, and then watch the video too, to ensure that I fully understand why I got the question wrong and how to get it right in the future.

I'll just echo what lots of people here are saying, and what I've heard various LSAT test prep professionals say, don't rush it, you can, and really should, take a year, especially if you are not scoring the best you can possibly do. Just keep studying until you get your best possible score, then sign up for the test. No need to rush it.

I think the point is to ignore the difficult vocabulary and just understand the argument behind the use of such complicated terms. I am guessing the lexical specificity is such in most cases that, unless one was actively involved in that particular field, few normal people would be able to understand it.