Application rates may vary based upon the depth of shade users desire. The best Endurant application rate is also listed on the container for home users and professionals. Apply more for a deeper result if desired, but do not mix at a rate that is overly diluted. Maintain the 15:1, water to Endurant, mix rate.
The best Endurant application rate is the one that stays within recommended guidelines on the bottle. After that, it's a matter of preference if you want to apply more colorant for a deeper color result.
Generally recommended rates per acre for golf courses are: Endurant Fairway (FW), Endurant Premium (P+) & Endurant Perennial Rye (PR) at rates of 6-10 gallons per acre for fairways and rates of 2-5 gallons per acre for greens; Endurant TE at rates of 16-32 ounces per acres on fairways and 4-12 ounces per acre on greens.
Recommended mix rates are 15:1 water to color. That's 15 gallons of water to one gallon of Endurant, for example. DO NOT DILUTE to lower rates. This could affect the durability of Endurant. When diluting Endurant beyond this 15:1 rate, using more water doesn't just dilute the color, it also dilutes the binder. This could prevent Endurant from lasting as long and staying on the leaf blade. For this reason, use the recommended mix rate. However, if you want a deeper color result, you may apply more Endurant or more coats of Endurant.
Links to product labels and to buy Endurant now are here.
For more on getting the best results, consider reviewing these two pages:
How to Choose the Best Colorant for Your Grass Species and Type