a .662 ball seems like it would be a rattletrap down the bore of a 12 gauge, even in a wad. a .690 ball in a shot cup will pass through a full choke. it just cuts the petals off the wad at the OD of the ball.. winchester WT12 wads are thinner than the waa12 wads on the petals. they work better for me. I load mine in federal game/multi-load hulls, they are thinner than the compression formed hulls and have a good internal volume, plus they are everywhere at the range.
all that being said i am really partial to the .735 ball loaded to 1400 fps.