Unfortunely it is a re-formulation of a polysulphide based tone with selenium. I don't know if the new version contains selenium. You will have to check the label. (but i don't think so)
Yes these toners do have a strong odor.
They will have a stronger shift on warmtone papers and if you are looking for rich brown tones definitely use warmtone papers , the use of warmtone developer may enhance the tone
Be sure the prints are fixed in fresh fixer and washed carefully.
have a "stop bath " on hand as toning will continue when washing. You can use a 10% sodium sulphite bath, or HCA (this is used after the toning)
If you are going to use this as an indirect toner be prepared for a loss of density; just increase exposure, if direct toning, there may or maynot be a loss depending on the paper.
You can use other toners after, i.e.gold.
Use at 1:24. or test out other dilutions. It is up to you. These toners seem to increase strength with higher dilution ratios and need to be watch carefully as they will continue to tone with washing.
It sounds more complicated than it is, have fun and experiment.
Check out Tim Tudman"s book on Toning for more indepth information.