Mixing Veg Oil with Diesel to power a generator

[NorthernRaider]

I've seen various chats about running a diesel genny on mixes of derv and veggie oil, Some claim veggie oil in to high a concentration damages injector pumps seals, some same its only feasable in warmer weather. Some say you add parafin as well in cold weather, others say you add acetone to up the cetane rating. I often run my Transit van on 80% derv 20% veg oil but I'm a coward when it comes to my vehicles engine.