Don't quote me on it, but I think the Lee .600" round ball mold is appropriate for 20 gauge. I use it for a tri-ball load in 12 ga, never tried it in 20, but I vaguely remember the 20 ga guys talking about using that one. Just remember to get that mold extra hot, cut the sprue while it's hot and soft, to avoid damage to the mold blocks. Lee's round ball molds have to be treated a little differently than normal bullet molds.
