don't bother with anything before In Absentia since they don't play anything other than Dark Matter, Shesmovedon, and Radioactive Toy (and they haven't played Toy this whole tour). Deadwing is a good idea.
Not exactly true, they have played other older songs on this tour too. At least Hatesong, Even Less and A Smart Kid. And on their last tour they also played some older songs like Buying New Soul and Don't Hate Me. Their setlist is changing for every gig they play so they'll probably play some other older songs as well. Though I agree that giving him old PT albums doesn't really give a good picture of what they are mostly playing on this tour. That's why I recommend both In Absentia and Deadwing.
This might help you, it shows what PT has played so far and how many times:
11 Fear Of A Blank Planet
11 Anesthetize
11 Way Out Of Here
11 Sleep Together
11 What Happens Now?
11 Halo
11 Open Car
11 Blackest Eyes
11 The Sound Of Muzak
11 Dark Matter
10 Lazarus
8 Cheating The Polygraph
6 Nil Recurring
6 A Smart Kid
5 My Ashes
4 Even Less
4 Trains
4 Half Light
3 Drown With Me
2 Shesmovedon
2 Sentimental
1 Mellotron Scratch
1 .3
1 Hatesong
And nope, I didn't make it.
