I've used standard Winchester AA wads and they worked well. First I ball up a little bit of newspaper and compress it by tamping it down on top of the powder to serve as an over powder wad. That seals the bore, protects the plastic base and cushions the shot load.
Then some more lightly compressed newspaper can work as an overshot card on top of the wad full of shot.
However CVA made some specialty plastic BP wads that are rated for a slightly heavier shot load than standard plastic wads.
I haven't tried them but they hold up to 1.5 ounces of shot rather than the approximately 1.25 ounces that a standard shot wad holds.
Plastic wads can also be overloaded a little bit too since the over powder wad will contain any extra shot spillage.