Here is the link to my DIY home brew drink mix. In short it is 1/2 cup maltodextrin, 1/4 cup fructose, and 1 nuun tab for electrolytes and flavor. This gives a 2:1 maltodextrin:fructose ratio. Even though the measurements are in cups (e.g. volume) I have double checked the weight on a scale and it is well within measurement error (e.g. 1/2 cup maltodextrin = 60g, 1/4 cup fructose = 30g).
If you’re looking for 1:0.8 then you could do 1 cup maltodextrin and 3/4 cup (heaping) fructose. Should be close enough. You just need to figure out how to split it across your bottles since that will be 210g carbs.