I'm speaking only from my own experience but I have a B-17 standard and 2 B-17 Narrow saddles that were all purchased new. The standard B-17 started to sag after 1,000 miles or so and I have since had to tighten it slightly and lace the sides to maintain optimal comfort. In comparison the Narrow versions seem to have a little thicker leather and have some flex but no sag. I'm 165 lbs so not a real heavy weight on the saddle.
IMHO I think with the use you intend for the saddle and based on the extras you get with it I would opt for the Select.
__________________
Nothing compares to the simple pleasure of a bike ride - JFK