In my opinion, there is really no difference. If you are talking about 'vintage-voiced' strat pickups, the output levels might be something like N=6.0, M=6.5, B=7.0. The difference in 'hotness' between a 7.0 and a 6.0 would not be so bad as to be intolerable. Heck, I would barely notice it.
I have a 10k output hotrail in the neck position of my strat, and two singles of about 6.5 and 7.0 in the bridge. I keep the hotrail mounted low, and the other two a bit higher to keep the balance. No biggie.
Personally, I like all 3 pickups to be at about the same level because I use them all for the same reasons, I just choose based on my mood.
Also, I really doubt if the neck pickup in a Jag-Stang has adjustable poles. In fact, I'm not sure I've ever seen a single coil pickup with adjustable poles.
In summary, I think the difference between 'hotness' would be barely noticible, and there is not specific 'design difference' between neck and bridge pickups except for the amount of windings. The only hiccup might be if you have a pickup set that is designed for a hotter bridge sound.
