My sprung B67 told me to pass this info on to your sprung Flyer. 
Mashing bits: When you go over bumps the springs compress, and for that moment the cantle end of the saddle is lower than the nose. It's as though you had set your regular B17 with the nose tipped up. (ouch) Try tipping the nose of the Flyer down slightly compared to your B17.
Tight leather: if you think the mashing might be because the leather is too new, beat on it with your hand or a rolling pin or something. (I've done that with the noses of my Brooks saddles.)
Creaking: Run some Boeshield or other oil into every bit of the nose shackle. There's a little ball joint in a cup at the very front of the shackle, be sure to oil that, too. While the saddle is still upside-down, see if you can make the creaking noise. Apply more oil to the spring area if that seems to be noisy. Follow with grease. (and if you get rid of the creak for a couple years, don't then go and toss your bike on the front rack of a city bus for 20 miles in the rain... cuz the damm creak will come back!!!!!
)
Mimi rides on the back of their tandem with a sprung Brooks. I'm sure she'll be along with better info!
"If Americans want to live the American Dream, they should go to Denmark." - Richard Wilkinson