Iron Counter Support Brackets can carry significant loads but they must be securely fastened to the mounting surface with continuous blocking, or double-stud construction. When mounting into wood studs ”toeing” into the stud will ensure that all screws are fully engaged. If toeing is not an option align the bracket so that 1 top and 1 bottom screw are fully engaged. When installing into metal studs you must block the steel studs using wood studs by either piggy backing or sliding a wood stud into the C channel metal stud.
Weight capacity is based on evenly distributed static loads.
Bracket spacing is based on the weight being applied and the countertop material being used. Different countertop material can carry different spans. Consult your countertop supplier if you have any questions or keep your spacing at no more than 24" on center be safe with any application.