From what I have heard it takes a very long time (like years of continuous cloning) for the genetics to begin to degrade. Many people with pretty large set ups don't use mothers and just use this method. As far as fimming you were linked above, but basically it is just a form of toping where instead of taking the entire top node off you cut just above the top node which can provide an extra top or two, basically it is no different than topping just an optical illusion because the new top comes up immediately after the node that you have cut above.