I think if I were in that boat I would grab a 7/8" ball nose end mill and make a pass about .050" deeper. I'm sure that would make a significant improvement. I wouldn't want to take more than .100" though as that may put the adjuster into a really funky angle with the pushrod.
I guess the main thing I take away from this is that even though the RHS LA-X is marketed in a way that makes you believe that you can use your existing shaft rockers from your early LA heads--This is simply not the case as evidenced here. I have a set of RHS's on the way so I can do some testing. J.Rob