In 50+ years of doing battery maintenance and fixing charging systems, I've never heard of "setting" a battery at less than its full output.
One thing that will drastically reduce the current capacity is letting a discharged battery sit around without recharging it. The soft, spongy lead sulfate formed on the surface of the plates that is a normal byproduct of discharging will form hard, stable crystals that are nearly impossible to re-dissolve by recharging. The part of the cell plates covered with sulfate crystals cannot enter into the chemical reaction between the plates and the acid, and the cranking capacity and reserve drop to nearly nothing. Once a battery gets sulfated, the only cure is repeated slow charging and total discharging, possibly 10 cycles or more. Even then, some batteries never recover from a severe sulfation condition.
Jerry
