The auto shifting is happening in the 48 tooth front gear and the 4th largest cog on the rear. I think that the 4th cog is a 20 tooth.

3/32" wear over 12" is 0.7% wear. I thought that you could go as high as 1% wear. What percentage wear do you guys shoot for as the max wear on a chain?

As far a chain lube, I drip some motor oil on the chain about every 100 miles. Then I just let the chain sling the oil all over the rear wheel and wipe things down about every 2 weeks. Since I only do hill repeats it takes me about 6 months to put 500 miles on the chain. I did make an exception this weekend and rode 63 miles on a course with only about 3000 feet of climbing.