If you haven't, you might check the alignment of the derailleur cage to the chain to make sure its straight.

Also, if you have barrel adjusters, you might want to experiment with the tension.

You might have two much high from the cage to the chainring - depends on which "coin" you are using. If i'm not mistaken, my 105 FD instructions called for about 1mm of clearance from tooth to cage. Most of my issues went away when I fixed that

best of luck and nice bike - I love Rivendells