Its on the WVO side of things, but a handy automation would be a PLC that monitors the WVO tank's temperature and automatically switches the fuel solenoid when it hits the target temperature, monitors both the WVO and the diesel tank's fuel levels, and automatically switches the solenoid back to diesel and keeps the engine running for a short period after the key is turned off, to purge the lines of WVO for the next startup.
I've seen several homebrew implementations of this, none of which have worked all that well (but not to say they couldn't work well).
peace,
sam