After a bit of reasearch and some advice from the forum I have now made some modifications to my hilux to make it run better on a diesel/veg oil mix 50:50.
I had 2 issues:
1) it was a pain to start on cold mornings, as cold oil gets thicker.
2) running cold oil was likely to be leaving oil deposits in my engine reducing engine life.
So, ive done 2 things, I now have injector line heaters which are run off a relay thats activated by the glow plug timer. so when you turn on the ignition and your glow plugs come on the injector line heaters also turn on and off at the same time. This made cold starts perfect again.
Next was an inline fuel heater which runs on a thermostat, the thermostat makes the heater turn off at 80 deg c, which is apparently the ideal temp to have veg oil at. it is then a similar thinkness to diesel and thus atomises better through the injectors and gets a more complete burn - less carbon. This is hooked up to a relay from the ignition.
So here are the inkector line heaters which are wrapped in a black silicon tape to insulate them a bit and keep the element in contact with the injector lines.


here is the fuel heater, it is 75cm long so i had to fit it along the fire wall behind the fuel filter. it runs betweent he filter and the fuel pump.
its the red thing.

the little bit where the wires are is the thermostat.

Result - well it costs about $150 all up, and the car starts like a dream in the morning, the inkector line heaters have done an amazing job.
The fuel heater is hard to tell, its long term results are hard to gauge, but im sure it will be better. It may also result in a little better fuel ecconomy as the combustion should be more complete. Im also hoping that by running warmer oil through the IP, it will be under less strain and also less likely to build up any residue from the oil as any residue should dissolve with the warmer fuel.
if anyone wants more info let me know.
see ya