My 'bible', "Dictionary of Photography" (19th Edition, 1961, Iliffe Books Ltd., London) Sowerby, A.L.M. (ed), pp 380-381 gives the following formula for hypersensitising film:
Alcohol (90 per cent) - 8 parts
Ammonia (0.880) - 1 part
Water to - 32 parts
"Immerse panchromatic materials for about five minutes. Dry as quickly as possible in absolute darkness and use within a few hours. The speed can often be doubled (increased by 3 degrees B.S.) in this way, but there is a distinct tendency to fog."
It also mentions using sulphur dioxide as an "effective, safe and reliable" method of hypersensitising. Exposed film is loaded into a sprial, then placed into a lightproof container such as a bisuit tim over an open vessel half-filled with a mixture in equal parts of sodium sulphite and glacial acetic acid. Develop normally after 24 hours exposure to the sulphur dioxide. The book reports a doubling of speed or a little more.