Kyle - I've only built one take down recurve (I'm more of a longbow guy), so I am by no means an expert.....The length of the wedge will influence the weight of the bow by affecting the length of the working limb. Longer wedge = higher weight. As far as wedge thickness, I'm not sure since it all tapers down to nothing anyway. You can make the wedge square for a couple inches on the thick end before the taper starts. This will give you a square surface for the bolt. If you go with two parallels vs. a parallel and tapered lamination, the weight will be higer. I'm not sure what it would do to the performance.
You might want to get Bingham's instructional materials and follow their plans for your first one. Then once you've got some experience you can set out on your own design.
Good luck,
John