Inserting even a short PK-11a (8mm) between a lens and TC should provide sufficient clearance for most lenses, especially if the rear lens is already slightly recessed. However, whether adding extension and a TC to a lens will give good results remains to be seen.
This will result in a close focusing 190/2.8 lens. If such a lens is needed, perhaps the Tamron 180/3.5 or Sigma 180/2.8 macro lenses would be a better choice.