My father has mastered the manufacture of a really high quality diesel fuel, from waste cooking oil. I takes him about 3 days to make 45 gallons with all the washing cycles. He has been running it in his Cummins and VW engines. I have run it in my duramax with no issues but no more than 25% mix with regular diesel. Is there any issues with Bio I should watch out for? can I use a higher % of bio?