I could kick myself for not thinking of this on my own. I actually found this info in THT, and it makes really good sense. It is probably too late for my rebuild, but hopefully those doing rebuilds in the future can benefit from this info.
As we all know, getting water on the deck, through the scuppers, is a common problem, especially if we put a 4 stroke on a bracket or do something to increase the weight in the back of the boat. We raise the deck to compensate, which hopefully keeps the deck dry under normal conditions. But when a couple of guys move to the back corner to fight a fish, that corner gets pretty low and feet get wet. Sure, ping pong balls scupper covers could be used, but not everyone is a fan of those. Plus those are subject to leakage, blockage, etc.
The solution discussed on THT is to route the drain hose from the port deck drain to the starboard scupper, and from the starboard deck drain to the port scupper. That way, for example, when the weight is in the back port corner of the boat, the starboard scupper should be well above the water, thus not letting water in. And although the port scupper would be well under water, the other end of the hose (aka, the starboard deck drain) would be well above the water, also not letting water in.
Obviously this will only work if you have deck drains plumbed to thru hull scuppers. If you just have the drain tubes through the transom, this will not work. On my boat, I will have deck drains, but my stringers are full height all the way back to the transom. I would have to notch them or put holes in them for the hoses to pass from one side to the other. But since I put my rigging tubes inside my stringers, I dont think I can make that work (but I willl look at it closer just to be sure). Anyway, hopefully this information will be considered by someone just starting a rebuild or doing one in the future. I personnally think it is a great idea.