I find it interesting that the hot stage jettison is after the boostback burn. That implies to me that the purpose of the jettison isn't for weight reduction. I wonder if there are aerodynamic control reasons to jettison the hot stage.
I also wonder if the hot stage ring is expected to sustain enough damage to be a single use part anyway.
My wife got repeated infections and had a lot of pain from the copper iud.
If you go looking for testimonials you'll find numerous people who had bad experiences with it.
Also, they really should offer anesthetic or at least a powerful painkiller for the insertion and removal procedures. Doctors act like it's no big deal, but it's very painful.