Thanks Bob I am always open to suggestions from the lord of the flies. I really, really like my streamers to have a jigging action, and for that you need serious weight.
The flies in the picture - they have 1 small conehead, followed by a large conehead, followed by another small conehead. So there are 3 coneheads total in each fly.
I am going to try these and see how they swim. I suspect they should swim fine. If they need more weight I will do as you suggested, add wraps of lead and slide them up under the last conehead.
The hook is a sz 1 Gammie Octopus hook. I am hoping the short shank hook will hold all the monsters I will stick.