Very, very intersting. As to say: goodbye weed guards, welcome springs.
I was thinking that the ring at the base of lead, over the hook's shank, must not be thick, must not be strong, it must be only a connexion ring for the spring, so it's possible for instance to create a little ring with a pc. of wire Ø0,4 mm over the corner of hook, place it inside your usual, not weed guard, jig mold and pour the lead. Of course you will obtain a little bit of shaves, but perharps this trick's worth it.
Just an idea.