I have cracked the Silver Bullet and created some things I'm really happy with! None of them are Etsy-worthy, but great reassurance that it can cut some very very intricate cuts on cardstock. It's hard to tell from the pic, but refer to the size of my thumbnail, and then the size of some of the icons including the rod with snakes and the heartbeats, and the heart with a heartbeat running through it at the bottom right. These are *tiny* and cut perfectly. The cardstock is Kaisercraft about 200gsm (not sure that that is in lb, sorry), and from memory I used a 45 normal (not detailed) blade and speed of about 100 and force of about 125.
Where I'd been going wrong was using the normal (non-click) holder and the 60 degree blade. It seems the 60 degree blade catches and tears whereas the 45 blade cuts through cardstock like a hot knife through butter. So I'll save the 60 blade for cardboard and vinyl, I guess.