Re: 50s Strat pickups vs 60s Strat pickups.
On average, early Strat pickups pickups have a few hundred fewer turns than early '60's pickups. But the word "average" is very important to understand in that statement. When making generalizations about the original Fender pickups, the pickups have to be summed up by these "averages" due to their inconsistency. But now, it's kind of backwards, and we have reverse-engineered pickups that are made specifically to fit the old averages. Instead of making their pickups "loosely," i.e. with a lot of variability, and letting the average establish itself, modern manufacturers force their pickups to fit certain pre-existing averages by precisely controlling the way their pickups are wound. So it's easier to generalize "'50's" and "'60's" when you're talking about what they mean to modern pickup makers, not to the original Fender pickups.
Long story short, to a modern pickup maker, the '60's style pickups will be a little bit darker and a little bit higher in output than the '50's ones. If you're talking about old Fender pickups, it's more difficult to predict how any one pickup from any period will sound.
However, I personally find the differences are not that great. IME, they're close enough that either type can fairly easily be made to sound pretty much like the other, if you have a good amp and you know how to use it.
