Design parameters for Keel Pad

When looking at posted photos of the construction sequence for Ken Basset's runabout design, RASCAL, I noticed the keep pad design which is supposed to markedly improve planing performance. The keel pad appeared to me to resemble a large waterski integrated into the bottom of the boat. Since I am working on a design for which it wouldn't be too difficult to incorporate a similar design feature, I am wondering if I can get some advice on any critical parameters. How fast do you need to be going (19' hull) to make a keel pad worthwhile? I suppose that its area should be proportional to the supported weight and intended speed range. Looks like it is flat for most of its length with a bit of upward curve (like a waterski) at the front. Any guidance on what portion of the overall chine beam should be included in its width? Any major drawbacks at non-planing speeds? Any internet papers which discuss this feature in detail? All help will be appreciated.