Wildcat fuels makes a Promix line that I've not seen before:
http://www.wildcatfuels.com/newsite/fuel_promix.html
as opposed to premium extra, what I use normally.
http://www.wildcatfuels.com/newsite/fuel_premiumx.html
I wonder if 5% of 18% total castor is good, or I should stick with 20% of 18% total castor.
What say you gentlemen?