Alot depends on your walking speed and sprayer output rates. For example, if your sprayer puts out 2-gallons per 1000 sf based on your walking speed, you'd want to mix at half the rate.
First thing you should do is put a certain volume of water in your spray jar with some dish soap. Say 10 total ounces. More for a large yard, less for a small yard. Set your sprayer to something like 1 oz (2 tbsp) per gallon. Spray and walk to determine how big an area you cover with a certain jar volume. you'll know you're almost out when you see the water change coming out of the spray to be less soapy. You can use die also, but I like soap, since it requires no cleanup. this will help you calibrate your ability to use the hose end spray. So let's say at the end of this you determine that in your 7500 sf yard, at 2 tbsp per gallon, you need three passes to empty ten ounces from your jar. Then you know if you use 6 tbsp per gallon, you'll cover the yard once. Or you can start with four vs ten ounces and only make one pass at 2 tbsp/gal. but you'll know your pattern better.
Then, what I do is try to calculate out the lbs/grams/ounces per acre of the product I bought. Back calculate the acres from square feet. Example -- 7500 sf is 1/6 to 1/5 acre. if the product requires 6 oz per acre, I'd put 1 oz in the jar. Then, fill the jar with water to dilute it - say add 11 oz water to get 12 oz in the jar. Add surfactant if indicated. Then, based on my calibrated walking pattern, spray at the rate to consume the jar after two complete passes. This way, I do not over-apply the product, and I increase the chances of it being applied evenly over the yard.
