We are not at 99.99, but a guy who hauls for/with us has been burning it in his 99 pete (detroit eng) since late spring.    He says "its cheaper than #2, gets as good or better mileage, same power, exhaust smells like french fries".    I can't smell the fries, but maybe my sniffer isn't good.

When its starts to get cold here, he will back off the bio.   We had gelling problems last year when the temp fell to around freezing.

Good Luck