Custom Cometic head gasket pics

Just thinking out loud here.... It seems to me, that if you wanted to get coolant past the exhaust valves faster, it would be best to plumb the rear crossovers and front crossovers into a manifold. The water flow would need to be reversed, so it comes out of the radiator, into the manifold, into the heads, and then you could pull either from the sides and front passages in the block's jackets, or just from the front to feed back into the radiator. I
I'm not seeing an easier exit for that coolant you're feeding into the block jackets. I think you're going to have worse hot spots and problems. Again just thinking out loud.