Don't the brass floats solve an already-solved problem? The current batch of neoprene floats aren't affected by ethanol. Whereas the brass floats rely on the integrity of a thin balloon of brass – if a hole gets abraded in the float, it sinks. Carb floats get holes in them all the time. I'm not sure why that's a design to be emulated.
I just redid my fuel gauge. The large inner gasket is cork/neoprene mix. Outer two gaskets are cork. Sealed up fine.