What are these Clark urethane springs you speak of?
Personally I run around with the 5 coil Spicer kingpin springs and have not had any problems with plain Jane Spicer bushings. The old springs were 4 coil, and once they get a little weak they create problems. I know some people have posted that the vehicle weight is somehow supported by the kingpin springs... It is not. All the vehicle weight is supported by the tapered roller bearings on the bottom of the housing yoke and knuckle. The upper kingpin is conical in shape, and the bushing that makes contact with it is tapered on the inside to match the taper of the kingpin. The spring basically controls the preload of the top tapered bushing and the lower tapered bearing (they oppose each other). I think the only connection between tire pressure and your wobble is this... With your tires inflated more the forces imparted on your kingpins are "sharper", more of a hit than a push. Because your kingpin springs are most likely the old 4 coil style, and have degraded spring rate they are incapable of keeping the two opposed tapered bearing and bushing surfaces preloaded enough to keep the knuckle steering axis rigid. So you drive around with kingpin springs on their death bed, really rigid tires, and your steering gets a bit of a jar, your upper tapered kingpin bushing gets shoved up into the cap a bit because the spring isn't doing its job, and presto your knuckle is now deflecting quite a bit from its desired axis, and you are mid death wobble. Once it starts it is self sustaining.
I have seen a 1008 where the springs were so bad that the front end had negative camber from the tapered bushing deflecting into the cap, just from the side load of the knuckle. I know you are planning on replacing them, and I believe that once you do the clouds will part, the sun will shine, and angelic music will chime from some part of your CUCV.
If you want another diagnostic test to judge the health of your kingpin system jack up and support the front of your vehicle on the axle housing. Leave the tires and wheels on for more hanging weight on the springs. If you can go under the vehicle and pry between the bottom of the bottom yoke on the housing and the top of the bottom of the knuckle with a small pry bar and cause any movement your springs are junk. There is a seal pressed into the bottom of the bottom yoke on the housing, so pry in a way that won't damage it. Basically you are trying to move the knuckle towards the ground, which is going to compress the bushing spring.
Keep me posted, I'm curious how this will turn out.
Also, you can adjust camber on a 60 with a different bottom pin that bolts into the bottom of the knuckle. The pin is eccentric compared to the bore in the knuckle.
http://img.photobucket.com/albums/v...a-2535-4977-a126-681712d8ba5a_zpsegdvrva9.jpg
See if the link to the picture works. You can pry where the red dots are. The picture is a cross section on the entire knuckle system.