To mix all components, one by one, each time you want to develop a film, is not that practical. Besides, with those 10% or 1% solutions you have to measure different amounts of each. I thought it would be easier to have only two prepared stock solutions and use equal amounts of them, just like a commercial developer.
So, here is my proposal for an easier usage of Bill Williams developer:
Stock solution A, for 500 ml
25g Sodium Sulfite
20g CD4 *
Stock solution B, for 500 ml
12,5g Potassium Bromide
0,1g Potassium Iodide
200g Potassium Carbonate
* The resulting amount in the work solution is slightly higher, 0,4g against 0,35g
Put 10ml of each solutions A and B in 500ml hot water from tap (+/- 50ºC), mix and let it cool to 45ºC (112ºF). Pour the solution into the tank, where the film was previously loaded. Gently and constant agitation during 8 minutes. Then rinse, followed by bleach, rinse, fix and wash, as usual.