I achieved success building glide baits thanks for the most part to the generous help of people here on TU.
For me, I carve the bait to it's finished shape, cut it into two section, and add my screw eye and pin hinges.
I ballast the two sections separately to get them to fall level, and at the same rate. I do this with all the hardware and hooks installed, but not painted, so I can alter stuff without ruining the finished bait. I use Azek PVC trim board to build my baits, because it is totally waterproof, which lets me test the bait as much as I need to, and the trim board is as buoyant as medium balsa.
Once I've gotten the bait to that point, I take it apart again. I drop the two sections, side by side, in a bucket of water, and add ballast as needed to get them to fall at the same rate. I add additional ballast equally to both sections to get the rate of fall I want once the two sections fall correctly. I use 1/4" lead wire in 1/4" holes in the belly to add or subtract weight.
Then I reassemble, and make sure the hinges are totally loose and free of friction.
I adjust the gap between the sections to achieve the amount of glide. The larger the gap, the shorter the side to side glide. Typically, for baits 5" and less, I want that shorter glide, so I can work them more in place without moving them away from my target area. 6" and over are smoother gliding, so the gap is tighter.
I try to make sure the bait tapers from thinner at the nose to the belly/hinge point, and then back down to narrow at the tail. I also try to make my baits thicker at the top than at the bottom, so they are more top buoyant.
Once you get a bait that glides, play around with the joint gap until you get the glide you want.
Lastly, I never use an O ring or snap. I tie directly to my horizontal line tie.
Here's my first glide bait, and it still catches fish: