Park sells three different sizes of their "loop type" spoke wrenches. The "Black" (SW0) is the most common size as all Wheelsmith, DT and other good quality spokes require it. The "Red" (SW2) wrench is used for older Japanese spoke nipples and the "Green" (SW1) is used for some unusual European spokes.
Take your bike to a bike shop and get the wrench that fits snugly on your particular spoke nipples. They are quite inexpensive.
As an aside, if you insist on riding off of curbs, you might as well use needle nose pliers to adjust the nipples since the rim will be damaged beyond use very quickly anyway.
If that was just a joke and the wheel is going out of true without abuse, the entire wheel need to be retensioned since that is evidence the spokes are way to low in tension. Find a bike shop with an experience wheel builder and pay him to properly true and tension the wheel and that problem should be solved.