I taper all of my jointed swimbaits, wider on top and narrower on the bottom.
I started tapering them to try and stop the baits from rolling on fast retrieves.
Tapering keeps them from rolling even when you burn them back to the boat.
For me, tapering from 7/8" at the top to 5/8" at the bottom removes enough buoyancy from the bottom to help require less ballast, and keep my bait lively.
I do this for floaters, too.
But I like my floaters to have just their backs exposed, so they "tail" on a slow retrieve, or on a pause.
Wake baits typically have more of the back out of the water at rest, so it shouldn't be quite as critical.
If you want it to swim sub-surface on a pull or faster retrieve, then you'll need to play with the shape of your lure to see what works.
The Slammer is a great wake bait, and it's basically a cylinder, so that should give you a starting point.
If you want to walk your bait, too, it needs to be slightly tail heavy, so the tail has more inertia and keeps moving after the head has been stopped on the pause.
Small walking baits, like spooks and sammies, hang almost vertical at rest.
The larger you bait, the higher the tail should float at rest, so you don't have to work as hard to get it up and walking.
Think of big walking baits as surface gliders.
I've never tried to make a walking wake bait, but if I did, I'd probably cup the face of the lure, rather than add a bill, to get the surface commotion. Think of how a Gunfish is shaped.
I think that would work.