Tim;
No heaters in the lines, my buddy runs a line from his water jacket through the bottom of his fuel tank, that heats it quite well. I run my lines down the water jacket outlet, that helps heat the oil. However, my genshed is well insulated and gets quite hot - around 90 - 100F in there most times. My fuel tanks are right up against the ceiling, so they get pretty warm.
I have not tried WVO in a DI engine, there is no reason to believe it will not work, but I suspect that if the oil is not hot enough at the injectors there will be significant coking. Other people may have more experience with DI's, amybe they can chime in and let us know how it works.