ATF,
I don't mean to be critical but what you're seeing is a change in the camber, not the tow in.
Camber is the angle of the wheel (measured in degrees) when viewed from the front. If the top of the tire sticks out farther than the bottom, it's a positive camber (which is what you're experiencing).
Tow in is the measurement of the distance from the front of the tire and the same measurement at the rear of the tire. If the front is closer, you have a tow-in condition.
On the RTV, the tow in is adjustable by adjusting the tie rod. The tow in should be between 0 to about 3/4".
I don't believe the RTV nor many other modern vehicles have adjustments for camber (unless you get into bushings and such).
I have the lift kit and am seeing the same camber conditions you do. Honestly, I don't worry about it. I have not seen any unusual or related tire wear. If there was tire wear, I too may have a concern. Actually, if you look at several European sports cars (many Audi, Mercedes and BMW), you'll notice quite a negative camber, particularly on the rear wheels (for performance reasons). I've owned all 3 of the aforementioned vehicle manufacturers and have never encountered any tire wear issues related to the way the camber is set.
Also, my worries are squashed considering the amount of tread I have on the RTV tires vs. the life of the RTV. If you have 3000 hours on your RTV, you probably have about 30,000 miles (if you drive like I do). My tires/lugs on the RTV tires have a lot more rubber than a car tire so I'm expecting the tread to last at least that long. My guess is that I'll probably see dry-rot on the tires and need to replace far before I run out of tread.