I use Sinclairs and K&Ms. I changed the turning mandrels to ones that I made. They use bushings like those found on chambering reamers and are .002 under bullet diameter. I've made a few for friends and they spoke favorably of them. Bought the bushings from Dave Manson and Dave Kiff. I wish that someone would offer them for others to try.
The concept of an eccentric pin as offered by Pumpkin and Stiller (I think) is a great idea.