My quote of spring ID and length was not meant as a spec. but to identify, ( subject to memory lapse ), which springs I'd used from Reeves' range. They're 18g wire.
They work well on my Simplex and I quoted them as an possible indication for the Ajax, but of course the Ajax has 8 springs to 12 on Simplex, so the load per spring will be higher assuming broadly similar total weight, but at about 50p each the cost of experimentation isn't too high.