After you've thoroughly triple checked all government, federal, state & local records, documents and data, Fold 3, these message boards and lots of diligent time, effort and posts couldn't hurt. Guion Miller applications & Dawes cards are a huge help to Native American researchers, as well as pensions, wills & family bibles, old diaries and your elderly relatives can also be of help too.
You have to keep checking the Guion Miller applications, as more & more of them are being transcribed daily. One day in the not too distant future, you will be able to use a giant mega search engine specifically designed for Guion Miller applications. Now, you have to decipher the cursive hand writing on them yourself, which can take lots of time, & some names, places and dates are extreemly hard to read, for various reasons.