I can't help with the individual formations, but Butlin (1988) shows the Overhead's carriage types were numbered separately (i.e. there was both a motor 1 and trailer 1), however set formations were not sequential. Latterly, formations were at least semi-permanent as the carriage numbers were displayed in the guard's cab.
Motors 32 and 35, plus trailer 5, were lost to fire at Dingle in late 1901. A new trailer 5 was built but the motors were not replaced. A further six trailers were also added between 1932 and 1936, these being converted from motor cars 31/33/34/36-38.
The above changes left the overhead with a fleet of 19 three-car sets: 38 motors (numbered 1-30/39-46) and 19 trailers (numbered 1-17/47/48). This remained the case until the Seaforth Sands fire of February 1956, when motors 2 and 12, plus trailers 4 and 6, were destroyed.