Simon is right - we did the big search for 100% Deet only to learn later that we did not need anything that strong. Taken from a website about repellents: "Concentrations of DEET range from about 5% to 100% and, generally, products with higher concentrations of DEET repel insects longer. However, at some point there is not a direct correlation between concentrations and repellency. For example, 50% DEET provides about four hours of protection against mosquitoes, but increasing the concentration to 100% provides only one additional hour of protection." The 100% stuff smelled much stronger, was more expensive and didn't work any better as far as we could tell. Deep Woods Off has aobut 33% Deet and you shouldn't need anything stronger. Regular Off has 15% Deet and will need to be reapplied hourly.
As for the Skin So Soft - no scientific evidence it's effective - same website says to the extent it provides any protection at all, it's "a weak, short-lasting (less than 20 minutes) mosquito repellant."