To me Donald Grey Barnhouse is somewhat enigmatic. He studied under R. A. Torrey (a dispensationalist) at (what is now) Biola, circa 1915-1916, then studied some at Princeton, leaving in 1917 to join the army. Eventually he earned a ThM at Eastern Baptist Theol. Seminary circa 1925. He accepted the pulpit at Tenth Presbyterian. in 1927.
He was considered a conservative, a fundamentalist, and part of the Neo-evangelical movement. He remained a Premillennialist and a moderate dispensationalist. Barnhouse died in 1960. As you know, Jim Boice took that pulpit in 1968. Boice was also a Premillennialist, but not a dispensationalist. I wouldn't call Barnhouse Reformed.