There is information about strength of solutions
here but it does warn against pets having access to this particular disinfectant whilst in solution so not sure it would be safe incase the dogs licked their paws. Different went applying it to a surface and allowing to dry thoroughly but don't see that being possible on the dogs fur.
To be honest I think you could be wasting your time anyway as, although the paws will have had most contact with the outside world you cannot disinfect the whole dog :) Probably just washing off obvious dirt with normal detergents is all it is worth doing.
More info on solution and how to use.
http://www2.dupont.com/Virkon_S/en_GB/applications/disinfectant_foot_dip.htmlQuite a palavour really :)