I have the final version of Charis SIL Modified Larger. I've fixed it so it works on the Kindle in Mobi & KF8 as well as working with ADE. It is no longer in beta. Enjoy.
P.S. If you do try this on a Kindle Touch, you will have to delete the existing Charis SIL Modified as you only get one Charis SIL Modified menu and I don't know which one it would be. On a Kindle PW, you can try it with both and see if you get both in the font menu.