Tifblair centipede seed should be applied at a rate of 1 lb. per 2,000 - 4,000 sq. ft. Almost all fertilizers, herbicides, insecticides, etc have treatments in amounts of so much product per 1000 square feet.  So if you can figure out what your walking speed is then you know anytime you apply any product that calls for so much of it per 1000 square feet, you always set your spreader on this setting.  You can calibrate this by marking off a 1000 square foot (10 x 100) area and placing 1.4 pounds of any type of product of similar granule size, or of the merit itself in the spreader.  Start with a low setting and start walking your marked off area at a normal pace.  You can adjust as you go and find the basic setting for you to apply the product over a 1000 square feet.