Had a Miroku Daly 28 with 0.000"/0.000" constrictions. Evidently, this was their idea of a skeet gun back in the late '70s. Well, no 3/4 oz factory load in #8 (or larger) could produce a 20 yd pattern lacking woodcock sized voids at pattern center. Some loads would let a grouse through.
I bought some 15/16 oz B&Ps in #8. Those got me all the way to 25 yds, just barely. But at that distance Rem 3" .410s in #7.5 through a "mod" M-42 looked better. So ended up selling the Miroku.
Larry's notion of 0.005/0.010 sounds good for a Maine woods 28 ga double. Unaltered M-12 28 ga skeet guns usually have constrictions close to 0.010" - that number would be my choice for a repeater.
