HOOSIERYOTE--Your post didn't make it to the Predator Hunting area, so I'll put this information here. Montana has a NO TRESPASS law now, so you are obligated to ask landowner's permission for any and all kinds of hunting. A couple years ago, you could hunt predators without asking the landowner, as long as he didn't have it posted for No Trespassing or No Hunting.
There are sections of state owned land, as in every state, but you have to buy a permit to hunt on these parcels.
As far as success with screaming or howling, I mix the two and have pretty good success. The howler will, in my opinion, reach out there farther to draw in distant coyotes. If you are close in to a coyote/s, then by all means use a low volume distress type call or even low volume coyote pup distress sounds. Good Luck!