As I explained to you via DM last week, the only flag that 4th Texas carried during the Maryland Campaign is in the game and it is the exact flag which the link you provided describes.
It was made by Wigfall and it is 4x4. It matches the artifact almost exactly, re: tilt of stars, etc.
If you find a historical source (not Pinterest, not Google Image searches, but Regimental Histories or academic work) which describes some other flag which was carried, I will happily look into it.
4th-tx.jpg