SGTiger has the B72 on her bike.
Remember, the B72 will require the "seat sandwich" adapter to put it on a modern seatpost.
The springs on SGTiger's B72 are much sexier than the ones on my B67. It is one elegant looking saddle... whoooo-boy!
I have three B67 saddles with the big coil springs. One of them has creaking issues, but the noise is in the shackle (nose) and will respond to determined and assertive grease application.
Springs probably do add a bit of weight (maybe the equivalent of a handful of change?), but I weigh a whole lot more than the springs, so I don't worry about it much.
"If Americans want to live the American Dream, they should go to Denmark." - Richard Wilkinson