While approximating gradients, using actual epsilon to shift the weights results in wildly big gradient approximations, as the "width" of the used approximation triangle is disporportionately small. In Andrew NG-s course, he is using 0.01, but I suppose it's for example purposes only.
This makes me wonder, is there a method to chose the appropriate epsilon value for gradient approximation based on e.g. the current error value of the network?