I was working out for some simple DIY stuff you could do to get better mileage when I went through the subject of vaporizing gasoline, it took me to this issue of injectors and how they perform. Various people in research have done test that conclude a higher fuel temperature would reduce the size of the droplets and even change the spread of the atomized petrol. They are only looking at temps of up to 80 degC for E85.
If you search for things like;
EFFECT OF FUEL TEMPERATURE ON SPRAY PROPERTIES
or
NASA ADS: Influence of fuel temperature on atomization performance of pressure-swirl atomizers
It will lead you to some briefs and summary. The FISITA link would be a downloadable pdf file on the test report. There are more results from various other tests.
I would think that this implies that changing your fuel rail to Aluminium would increase the temperature by a bit. Then it would only mean routing some copper tubes over the cam covers would help. Yes, the fuel is returned but some do get through the injectors. In the instance there is a need to get higher temps, then more hose lines need to be changed to copper finned ones. Which is fine for me as I live next to the equator. But where there is cold climates, its a matter of twirling around the engine a bit more.