Did you mean B17 on the saddle? I've never heard of the N17. Another option would be to go with the flyer (I recall you mentioning a thudbuster, so you could skip that with just a flyer):http://www.brooksengland.com/en/Shop_ProductPage.aspx?cat=saddles+-+touring+%26+trekking&prod=Flyer
I have a b17 and a flyer. Both are awesome. The flyer has more use so far, so it fits a bit better. They do take a bit of saddle time to get them to fit you properly. A bit of saddle conditioner (Brooks Proofide seems to work well) will help speed up the process. Just don't go overboard with it, or you will prematurely stretch out the leather.
Good call on going with clipless. Not sure if you have already bought or not, but I'm a big fan of Time brand pedals. Extremely durable and easy in/out.
Congrats on commuting with your own power! The first time is the hardest, and you are well past that.
Good luck with avoiding the overly entitled motorists.
And as far as hauling brew stuff, I have hauled 4 full kegs home from a friends house, 2 sacks of grain (along with other specialties, hops, yeast, etc...) from the brew store, and many other things. It just takes a long bike. But I have also hauled a 50 lb sack of corn sugar on the rear rack of my commuter as well.