I've been going down more rabbit holes regarding internal fly/lure design. Last night I listened to a great podcast with Joe Goodspeed regarding musky fly design and how he basically observed how gear guys were crushing them on these Suick lures that were basically a piece of cylindrical wood where the differences in action was provided by balance and weight distribution. What they did, instead of just a walk the dog style, was that combined with a sideways slide that slowly righted itself on the pause. Kind of like a glide bait with that extra sideways movement to it. He accomplished this with the addition of foam on top of the shank (towards the back end), then a keel weight set further up the shank (1/3-2/3 up the shank).
Below is my iteration of such a thing. I kept it really simple until I can see how it behaves in the water (my foam is large enough where I can trim it down if necessary). I ended up tying in some foam on top of the tail (rather than the foam discs I have used in the past), and then partway (1/3 of the way down from eye to bend) up the hook shank, there's a 7/16 lead eye tied on the underside. Rather than coat the head with silicone like Joe does, I just made the head more dense (I used about 4x as much titan dubbing for the head than I normally do)....but you want a thick head to push that extra bit of water to draw in fish that may not be able to see the fly.
