Use the spoon in the bottle or a damn fine scale. I think for hand touch up you mix .9 gram, yeh thats right .9, one LEVEL spoon/gal of water. It doesn't dissolve right away, so mix and mix and mix, then shake when you get to the job and shake while you spray. Also use the 1 oz/gal or whatever of non-ionic surfactant as they say. Spray till wet like they say.
It's great on nutsedge. You'll get more but it'll be from other nuts. I sprayed some 3 times this summer and it was significantly less the second trip and almost none the 3 rd. I'll watch next year.
Only mix what you will use immediately. Letting this stuff sit over night or 24 hrs in a tank kills its effectiveness. It's active ingredients are not stable in water and it degrades. I learned this at Rutgers University this past summer. I also left some in the tank and sprayed the following day at home to check and it didn't do squat.