I'm trying this with a Wilson putter I like the look of! So far I got the outer rubber off but it looks like there's an inner layer I need to deal with too. I'm going to custom make my own insert using recycled HDPE
If anyone has to replace the white discs on top of a Odyssey 2 ball white hot putter, go to Shapeways they do 3D printing and have the Front disc and the Aft disc. Knock out the original discs and thoroughly clean the holes. Once cleaned the discs should fall into place with some crazy glue.
If you are looking for a quality insert at a fraction of the price I have 2 examples you can try. One is a resin insert. The other is using a polymer clay. There are many types you can mold to fit the face and sand to the correct finish.