You can get you a Turkey Lounger. It is obviously made for turkey hunting, but a lot of people use it for predator hunting. That and a nice pair of shooting sticks will allow you to both set up a bit above the grass and get a semi-stable rest. Be careful not to over call the spot. If a coyote or two comes in and senses something it doesn't like, it can make a quick exit without you even knowing it was there! Then if you continue to call for that long, it can educate them to associate that sound with man and stop investigating it. Most predator hunters will call a spot from 15 minutes to sometimes 45 minutes. The later when bobcats are expected! Probably 95% of called coyotes come in between 3-12 minute mark. You will have some that break the rules. As for the coyotes ALWAYS coming in from the West, there is no always when dealing with coyotes!
Once you think you have them figured out, they will prove you wrong!