Dave;
"Bosch distributors are notorious for closing the points gap despite proper and careful initial setting." I can't agree...and it's the first time I've heard of that...maybe your initial setting wasn't as "proper and careful" as you thought...I got 50kMiles from one set of points as a long-term test, and I finally changed them out of guilt (and because Centrifugal Advance was frozen)!
See:
http://www.sw-em.com/tuneup.htm
Cheers