i did a little more research and found out the following.
The Army post flag was 10x20 feet, also with the union extending 1/3 of the fly. The six-inch stars on this flag are shown as 8-7-8-7-8, lined up vertically, with the extra stars in the rows of eight in the fly. (Specification dated May 31, 1876)
There was also an Army storm flag, 4 feet 2 inches by 8 feet, with the union extending 1/3 of the fly, with the stars as in the post flag but the eighth star in the longer rows in the hoist. (Specification dated December 31, 1877) this is the flag configuration i have.
I just ran across a 1986 reprint of a book issued by the U.S. Army Quartermaster General called Specifications for Clothing, Camp and Garrison Equipage, and Clothing and Equipage Materials (Philadelphia: Philadelphia Depot of the Quartermaster's Department, 1889). It includes a number of flag specifications issued between 1876 and 1889. Taken in combination with the contemporary U.S. Navy Tables of Equipment and Flags of Maritime Nations (1882), it is interesting to note the variation in official proportions and designs of the S&S at the time. Looking at the flags side by side also lets one see why President Taft felt the need to standardize the design by executive order in 1912.
Joe McMillan, 9 February 2001