Is this the chuck you are using? https://www.shars.com/5-er40-zero-set-fine-adjustment-collet-chuck
This is new territory for me. Which back D1-4 back plate should I use?
Perhaps this one? https://www.shars.com/5-d1-4-threaded-black-place-for-er40-zero-set-adjustment-collet-chuck
Yes the Bison set is nice, I lucked out and found it new on ebay 250 USD. It is just a 16 piece set but it is pretty nice.
It sure makes collet change easy on the mill without a power draw bar.
Yes, I believe that's the setup I use. I would email them first to verify compatibility though. I did have to machine the center boss a little, but it's designed that way so you can be sure it's concentric etc..