We don't carry that particular model spreader, so we are not sure what the exact settings would be. The easiest way to determine the correct setting for you needs is outlined below:
If you need to use 3.6lbs of product per 1,000 sq ft you would add 3.6 lb of product to spreader, start with a medium setting, then apply product to a 20 x 50 ft area (1,000 sq ft). If you have product left, your setting is too low. If you run out of product, your setting is too high.
We would need more information in order to answer your question efficiently.
What state are you in? What type of grass do you have?
Pendulum 2G is a pre-emergent and would normally be put down in early March to late April before the weeds have germinated. This will depend on the area that you reside.
Most weeds begin germinating when the soil temperature is 55 - 60 degrees, so it is best for you to apply this when the soil temperature average is 50 degrees. We would recommend contacting the master gardener at your local county extension office as they will be able to give you an exact time frame for applying this product in your area.
Pendulum 2G can be applied in early spring to prevent field sandbur, and it can be applied in the late summer/early fall to prevent lawn burweed. Many areas of Texas have had a more mild winter than usual this year, so a lot of field sandbur has been behaving more like a perennial than an annual. In this case, you may need a combination of pre-emergents and post-emergents to get satisfactory control. Keep in mind, too, that the best defense against sandbur is healthy, thick turfgrass.
You can consider a pre emergent like Pendulum to spread for Burweed in your Bermuda lawn. This should be put down before germination.
You can fertilize before, during, or after application of Pendulum 2G Granular Herbicide. The healthiest, hardiest lawns are fertilized 4 times per year, fall, summer, early spring and late spring.
Application timing of Pendulum 2G - 40 lb. will vary by region and the best person to ask about application timing is your local master gardener who works at your local cooperative extension office. This is a pre-emergent product only and will not kill any weeds that are actively growing, it only prevents them from emerging. It cannot be used around anything edible but can be used in lawns and ornamental landscapes, how much you use depends on the type of grass you are applying it to and the program you are using, generally pre-emergents are applied 2 to 3 times per year. 40 lbs can treat just under 1/2 an acre when used at the 100 lbs per acre usage rate. Please take a few minutes to read the Pendulum 2G product label to find the usage rate and program that is right for your needs.