NOTE Please check your old lead ends if they are worn or shabby you may want to invest in a 1/2 lead repair kit to keep your cell running at optimal performance. Solid plate is easier to clean. The calcium just falls off.
Of the time compared to mesh cathode. In a cathode they last longer (as they have up to 3 times more material than mesh). There is no problem with using them in place of a mesh cell. The cell will be replaced in the first 2 years if any manufacture defects are visible.