MY fence is a lil over 5 feet high.. to add on those extensions would give me an advantage.. at least on the side of my house where there is a field off to the side and on the backside of the houseI like b. and c. in the first diagram. I've seen a few cases of failure in the Predators section of the forum from folks using the a. method. The middle picture looks great, I'm not sure how effective the last one would be, I suppose it would depend on the height of the fence.