siitoin book is worth tracking down. I think print run is merely... 100-150? Lots of typos, very unprofessional, but utmost kult.
About Last Trax, I know nothing about.
I don't know where the "art book people" meet and talk, but I find it utmost hard to gather information about what are worth to buy and what are not. I buy probably 50% online, 50% in real life. So half of the time, it's either about buying the thing you know but cheaper, or just having a gut feeling that this could be something interestesting. I don't think I have bought any books I REGRET buying, but I do have some regrets of buying too many multiples of some books, which aren't that easy to deal forward.