Welcome to Detailing Bliss Gilberto
As for application, if you'r after a thin wax application you can't get any thiner then a foam applicator, applying by hand can waist qutie a bit of product. I personaly don't mind waisting a bit but Calgarydetail complains it's harder to remove...

wimp!
Seriously though, it comes to personal preference, if you want to make it easy on your self then use a foam applicator or try applying the wax by hand to a panel...say a fender and see which you prefer.
Just my