Luke, there's really not much one can shortcut on this,sorry.
A fully rifled barrel will ALMOST always do best with a sabot style slug, but only Heaven knows which sabot will work BEST in a given shotgun.
Were I starting out with a fully rifled barrel, I'd probably get some Lightfields and those Remington copper solids for starters, and go with the tightest grouping.
Realistically, any slug that groups into 6" or so under field conditions and from field positions is OK at that range.