I have no other information on the MADDRA line except for Martha who married Joshua RYON who was a brother of my 3rd great grandmother Angeline RYON who married Joel L. JAMES.It's possible that some of Martha MADDRA's family might have migrated with the JAMES famiy but if so, I don't have any information on it.
FromBedford County, VA marriage records:Oct. 27, 1823; Joshua Ryan & Martha A. Maddra, dt Martha; Lewis Lancaster, Surety.
Your GATTIS line's arrival in 1870 in Grayson County, TX is years later than the people listed above, who lived for a few years in Taylor Co, KY before moving on to Grayson County, TX.They left VA in about 1835, if I'm remembering correctly, and moved from KY to Grayson Co, TX in about 1850-52.
I checked a book I have "Kentucky Town and Its Baptist Church" by Joe W. CHUMBLEY for both GATTIS and MADDRA/MADDRY and none were listed in its index.Of course this doesn't mean that they weren't there at the time. Sorry I couldn't have been of some help to you.Good luck in your search!