The wobble can be the result of a number of things:
-loose headset
-loose QR's
-sub-optimal weight distribution on your bike
-maybe unbalanced wheels but the imbalance would have to be comparatively severe
-road defects
-???
Your best bet is to make sure everything on the bike is properly adjusted, torqued, and etc. Make sure your wheels are properly seated in the drop-outs and aren't misaligned.
Wobble is a resonant condition on the bike, which just means that at some vibration frequency, the wobble will increase in amplitude. Every rigid structure--bikes included--has a resonant frequency, and usually for a bike that frequency is outside of normal riding conditions. One thing that can most certainly exacerbate a wobble and even contribute to the initiation of a wobble is a rider who is not relaxed on the bike. In fact this is one reason why wobble's can be difficult for some to tame because when the wobble starts, the rider tenses up, possibly making the wobble worse. When you encounter a wobble the best advice is to relax and press your knees against the top tube. Getting weight on the front wheel helps. Apply rear brake, gently. Drag it a bit. Wobbles typically don't cause crashes but are certainly enlivening. Wobbles are speed dependent, so once you slow below the speed where it was initiated it should ease up. Should.
I had a monster episode of wobble descending Kitt Peak a few years ago, at about 40mph, just before entering a corner. The wobble made the line through the corner "interesting" and made corning a bit more intense than it normally is. After the corner, a bit of knee squeeze and relaxation, with a touch of rear brake killed the wobble. I finished the descent, making sure to stay below the speed at which I'd had the fun. The source of the wobble was a mechanical brain fart on my part just before the ride, a mistake which shall my remain nameless to protect my dignity.
I'd recommend doing the mechanical checks above and going back to Lemmon for test rides. Maybe just ride up to the Babad Do'ag overlook. On the way down, carefully build up speed, backing off if you start to feel the beginnings of wobble.