I've got a 28 ga two barrel set, and yes indeed the 28" M/F barrels are very tight. Even the 26" IC/M set patterns pretty tightly. If CSMC were to make 28ga barrels I'd be tempted to get a 28" set with loose chokes.

And I can confirm that the drawings for the Repros were made from measurements taken from guns in the extensive Parker collection owned by the Skeuse family. As an aside, they are all true gentlemen.