We were talking in PM's about blending clear mate, but apart from that I've a history in bike painting myself and the signs are there in your work. People who paint bikes work to greater detail than car sprayers, and I reckon you're using 4:1 2K primer there, pro stuff.
Lift pads are simply flat areas, often raised, on which the hull sits when at full chat, they are a more direct way of achieving lift. But, the prop also creates lift and I can imagine that the rear of that boat will come up readily, hence shifting the weight back. A boat's balance point is just a matter of center of mass, this used to be called center of gravity but with wider eyes it's now better to discuss mass in the absence of gravity, apparently
. That's all very well, but a boat's attitude in the water is also dictated by the hydrodynamic effects of water bearing on the shape of the hull. A static floating hull exhibits what's called a Meta-center, which is basically the center of the various mass and flotation forces acting on it. It's often in a different place, especially on planing hulls, and it moves according to the lift being experienced at a given speed. If it ends up in the wrong place the boat will either porpoise like mad if there's not enough speed to get through that, or run wet and heavy in the water.
For your boat though, and indeed with most, it's better to err towards rear weight than forward, as that is easier to adjust in the lightest manner. I.e. if ballast is needed then a little weight way up in the bow adds less to the boat overall than a lot of weight that would be needed aft, simply because there's more room (lever moment) up front to move the weight further for effect.
So, I guess Mart's 30% (from the stern of the boat) is where I'd be looking, given what I know of yours, as starting point.