At 320 ounces per 250 gallon tank full is 1.3 oz's per gallon of water. You will have to put this gallon out over a thousand square foot of area and cover 250,000 square feet or 5.7 acres.
I am using Vessel at 2 GPM or per 1,000 sq.ft. on 100 gallons. I think the concern for you is the over spray caused by forcing a gallon out over a 1,000 sq.ft. Z-sprayer and nozzles closer to the ground work best for this app.
The matter is not applying over 1.5 ounces per M at one given time in 5 to 220 gallons of mixture per acre is mandated.