hey! Have not been able to find any Dowflake locally or online so was thinking of using prestone driveway heat. How much do you mix up for a gallon worth? I read you should use 1/5 less than what the recipe calls for, so 2 cups correct? I have used BRS for my diy solutions but they have been out of stock for a couple of weeks with this covid stuff so I thought worth a shot making my own usong recipe #1 and save a buck while I'm at it. Thanks!