Parts arrived, but didn't fix it
RCBS sent out a complete shellholder assembly priority mail (basically everything attached to the top of the ram). Unfortunately, it didn't change the alignment any. That means it's probably the ram itself. The customer service rep said the next step would be to send the press in, but I'm not really anxious to do that. These things MUST be expensive to ship! Anyway, since I have a new spare part, I decided to operate on my original assembly. Yep, got out the trusty Dremel! I slightly enlongated those precisely drilled holes and got the rotation I needed. I plan to try it out later tonight, but it looks like it will work.