I haven't tried the paper shot collars yet, but have experimented with using a buffering material in with the shot charge. This was for a 62 cal/20 gauge cylinder bore trade gun, to be used for turkey hunting. Had fine ground corncob and walnut shell on hand, so tried these.
Experimentally developed loading technique is to instill the powder charge, then start the over powder wad, only running it in about two inches. Add the shot charge, in my case an ounce and a quarter of copper plated number 5. Add corncob buffer a little at a time, tapping on the side of the barrel to get the particles to settle through the shot. Once the shot column will absorb no more buffer, add over shot card ward. The corncob is finer than the walnut shell, and took less time to sift into place. Note there is no cushion wad.
I went through about half my five pound supply of shot in the various combinations of powder, wads, shot and buffer. At the start, using conventional load- powder, OP wad, cushion wad, shot, OS wad- I got 5-7 pellets into a turkey neck target at 25 yards. With the combination above I was getting 7-9 pellets at 25 yards, and 5-7 at 30 yards. Beyond 30 yards the patterns really opened up. Clearly 30 yards was max range with that gun and load. During the Colorado Fall turkey season I was able to ambush a fairly nice tom as a flock strolled down to Coal Creek for water before treeing up for the night.
Will try the shot collar approach soon. The Bevel Bros. used target paper, I will try that, and also the paper bags my groceries arrived in from Costco.