I found an old (1943) publication by "Camerette" Photographic Series called "Bromoil Printing Made Easy" by Hugo P. Rudinger which gives a bleach formula:

20 drops of pure sulphuric acid in 12 1/2 oz water. Then dissolve the following in the order given:
Copper Sulphate 1 oz.
Potassium Bromide 1 oz.
Potassium Bichromate 25 grains.

Then he goes on to say "This gives a stock solution which, for use, is diluted 1 part solution to 4 parts water..."