Take fresh tests.
I can't speak for anyone else on LSD, but this method would not work for me in particular. I have something of a photographic memory, and I recall nearly each and every question I've ever done for PTs. It's actually so bad that when I attempt problems untimed I cant check my answers progressively unless I take precautions against catching a glimpse of the correct answers for other questins in the corner of my eye.
Really though, if you aren't a freak of nature like myself, I would still recommend attempting fresh tests. You're likely to remember the general stucture of questions that you've encountered in the past, and this coaches memories.
In addition, have you ever had difficulty with just one or two problems on the LR section - that is, those questions that you mulled over the stimulus multiple times? You'll remember those.