Regarding concept 1, take a look at your transom while on plane. The transom should be completely out of the water...meaning the water level should be at the bottom of the transom. If your drain plug is stern-facing, it will be above the water level and draining. Assisting this is the force of gravity pushing the water in the bilge toward the stern. Even if your plug is below the water level, it will still drain if you are moving fast enough, gravity forcing water out of the bilge. The point between water filling or draining is a function of speed and gravity (inertia actually) on the bilge water...different for every boat and plug position.
I was on a 20' glass boat years ago...group (I say this to protect the guilty captain ;) forgot to put the plug in. Several hours into the excursion (lake MI) we noticed we were riding a tad low in the water... it took us a mile or more to get on plane. As we continued toward home, the bilge drained as expected, and the boat planed better as we continued on.
This is assuming you have a motor powerful enough to get your boat on plane of course...
And all of this was already said. Diarrhea of the fingers I guess.