At my old Trugreen branch we used 4 gallons of solution per thousand sqft. Rule of thumb was nitrogen at one pound per thousand sqft up to 80 degrees.
.75 pound up to 85,
.5 pound up to 90.
We used urea. And a small amount of potash as muriate.
Herbicide didn't seem to matter--we used a three-way.
We still burned a few lawns at times. Excess pressure and inexperienced people-- pressured to hit a high quota--caused a few brown lawns.