I have an H grade twist bbl Lefever with Bolted Doll's Head. Gun has been used & abused, bores look like a sewer pipe, has a crack in the left bbl, stock is held together with tape. I bought it "Cheap" as a parts gun but haven't needed any parts from it.But you know what it's tight & on face, even with the ball hinge pin completely removed with just the Doll's Head holding. I fail to see any useful advantage to the Jones Lever which would outweigh its drawbacks.

Miller/TN
I Didn't Say Everything I Said, Yogi Berra