I just followed instructions, and got a good bond. I would be careful where the aft end terminates so not to interfere with trailer support. My trailer has a "v-shaped" support for the forward part of the keel, and has a slick poly surface mated against the hull. My keel guard's aft end terminated a few feet forward of said support, and I figured all would be well. Murphy's Law comes into play, and sure enough, when launching my Pursuit all the weight is on the keel and sliding aft on this poly surface until it comes in contact with the keel guard, then oops...... the keel guard bond gives a little, and when you retrieve the boat back onto the trailer, you see a problem of 12-18" of de-bonded keel guard. My solution after putting another keel guard on, and having the same problem, was a) apply 3M 5200 to de-bonded surface, which had the same results, b) launch trailer much deeper in the water, which works, c) cut keel guard from 8' (if I remember) to approx. 7', which solved problem.
I sure like coming into beaches with such product and would recommend.
good luck. DAJ