Brad, you can play with the Auto-Wrap tolerance, might get you closer to what you want. Or instead of trying to tweak the cage you might try the sub-object controls, like hitting matching material IDs or setting up specific high-res meshes to only be captured by specific low-res mesh face-selections.
You could look into Kaldera
, it lets you specify a separate mesh object as the cage, which you could use Conform on. I doubt it would be worth the extra time though (or cost), Conform is not very accurate, especially when one mesh is much lower-res than the other. Better to limit intersections via material IDs or face/element selections, IMO.