Thanks for posting the pics, Greg. You are correct in that the offset is really the key. The expense and hassle of having the rims widened another 1" will improve the footprint and how the tire sits on the rim, but for most folks the visual and street/track performance would arguably be negligible (heck, you're running high 10's...enough said).
Another factor is how straight the body is set on the frame. My right rear tire actually comes up closer to the edge (by about 1/4") on my car than the left rear. I have also heard this to be true for several of the older cars, so I'm not sure if it has something to do with the 8.8 IRS and axle lengths or what.
Seeing your ride height adjusted darn near spot on where mine is gives me comfort that I won't experience a whole lot of rubbing.
-Dean