as others have said it depends on the question whether McK on the CV will help you in any way get closer to your goals since you will not be in a front-line consultant role. Would your potential post-McK employer value your experience higher than anywhere else? If yes, go ahead, accepting the pay cut.
If the answer is, however, no, I d not make the move. It comes down to you making the necessary diligence which most likely means calling a lot of people or finding them on linkedin or through your personal network - PL will not help at all.