Magnetic fields could be a helpful tool for improving the growth of nanostructures on metal layers during electrodeposition processes. It is well known that an electrode-normal magnetic field promotes the growth of mm-sized conical structures by generating a supportive local electrolyte flow. However, we found recently that for smaller cones of µm/nm-size, this local flow may often be superseded by a stronger global cell flow, thus preventing the structuring effect. We, therefore, discuss improved cell setups to minimize the global flow and to enable the magnetic support of conical growth.