Dennis, I don't shoot a .410, but regardless of gauge/bore, spreaders can be made by simply cutting two proper size overshot cards half way through and sliding them together to form an X. The X is placed in the hull and then the shot is added. If you use card and fiber wads instead of 1-piece plastic wads the effect should be a more open pattern. Shot, depending on the amount of antimony can also effect the pattern. Try a few different loads and hopefully you will get the spread that you want.

Jim