I'm surprised that jwl hasn't posted in this yet, he must still be doing his week long holiday partying. Rule of thumb is usually the bigger the bait, the bigger the fish but that isn't always the case.
I caught this Muskie one day close to dark on a 3.5 " perch coloured Berkley Frenzy crank that cost $2.95 on sale while trying for Pike when other tactics weren't working. Jack (jwl) can tell u that he's landed some good sized skis on his favourite 6" white twister on an unpainted jighead. I've also seen an 18" Pike take a bait almost the same length as it when I was watching a guy Muskie fishin' so u sometimes don't know what fish will take on the menu.
When fishing for Pike I like to keep it simple and stick with large spoons, Cleos and Williams Wobblers, suspending cranks, X-raps and Husky Jerks and also large Vibrax inline spinners.