some progress pictures - Here is my deconstructed medallion with the new center.
For reference - here is the medallion before I took it apart.
I used this for the ripping. I don't use it often, but it comes in handy when I've got some long seams to take out.
I got it all sewed back together - I like this so much better!
After laying it out on the diagonal with the 6" block I already made, I decided to make some 3" blocks so the setting triangles won't be so big. I picked easier ones that have a "star" look - and have most of the 14 cut out and ready to sew.