Whenever you are going to shed some Lacs make sure you are confident about yourself, because this thing is not for everyone especially the ones who know they struggled a lot during their CPL training and of course the overconfident ones. I am not talking on these MSD guys but in general, prepare well before any Sim checks, take those books, manuals and burn the midnight oil and practice instrumentations on PC flight simulators (there is a product called PMDG 737 its good to check out some stuffs on it). There are many who never thinks about these test, interview etc, if they throw out some money they assume they can get to the right seat straight away.