Bill,
I was thinking of the 3 disc scenario just for historical reference. I don't think it would hold a candle to just about any other version of spreader. I did try a few of those post wads (never fattened the post as you do), along with the X chambers, and a piece of soda straw. They all worked to some extent, but I settled on the Polywad Spred-R disc with 1/8 ounce loaded on top.
When you think about it, it's not surprising that setting off an explosion and throwing 400 pellets in the air gives a pretty pretty random result. Choke boring, followed by the shot cup, did a pretty amazing job of giving us some control of that helter-skelter event... virtually all patterns have a center core. Then, we go and add something to disrupt that center core. The layering technique ( 1/16, 1/8, 3/16 ounce on top of a Polywad disc) seems to offer some "control" of that core disruption. My spreaders....
LOVE those clear hulls!
I think we're in agreement that an evening spent making a season's worth of spreaders is not a high price to pay. I've never used a PW, but it sounds pretty convenient for use with the post wad. I load the PW discs on my 9000G and, whereas a regular box of shells requires 3 minutes to load, I can load a box of spreaders in 4 minutes.
Beware the man with one gun...he likely will bore you to death in others ways, too.