Hi Mark, I've seen Cadets with the struts that you mention. I've obtained the FAA airworthiness records for a couple of them to see what I could learn. So far, I've found no 337 forms on file documenting this strut installation.
My guess on the question of struts verses flying wires is that the Cadet horizontal stab is one piece with a heavy spar from tip to tip. The Cub horizontal stabs are two pieces and were designed to be supported by the wires.
There was a service bullitin concerning the Cadet longerons becoming crushed from overtightening the stab attachment bolts. I believe that the stab attachment is adequate if the longerons are undamaged. This would be a non-issue on the metal fuselage STF plane.