[Christ]

No input on whether it would help or not, but a pretty easy way to make sure your fuel is at least reaching coolant temps:

Use a radiator from an automatic, clean the transmission fluid line input/output by flushing, then route your fuel lines through that area.

This will ensure that your fuel reaches something close to the temps of the coolant, at least, which is a huge increase from the ambient temp that it is when it's being pushed through the lines.

Heating the fuel rail may not be good enough, since the fuel is only actually there for a very short time... it may not be long enough for heat transfer to actually occur, whereas in a larger apparatus, such as a transmission cooler, heatsoak will be more likely to occur.