As far as Jepps go, everyone in my group was asked about different airports. The outfit I currently fly for uses NOS, so I purchased the Jepp Instrument Procedures book, printed out all the online study materials I could find, and dug out one of my old jepp binders from my CFI days and read the legend numerous times. Pretty much overkill. If you do any of the above one time you should be good. I really get the impression that they are very good about picking like-minded people with a good work ethic. I almost got the feeling that they had their minds made up within a few minutes of meeting us. Whether that's true or not, the interview is a very pleasant experience all around. Hope this helps!
H&P