I would start from most recent and work your way back, personally. More recent test, I have read, are more likely to mirror the ones administered in the upcoming cycle. Any and all practice is a good way to go though!
I am in! I took my first LSAT in October and was devastated to receive a 146 after consistently scoring apprx 160 on my practice tests. I'm studying even harder and more diligently this time. Let me know how I can join the group!