I am pretty sure that the OP's "excessive gain" comment comes from the fact that he is using a stepper with 1db steps=24db of range. Nobody notices that they have too much gain when their volume controls are set to -39db 24db+15db=39db Considering that he only needed to knock off another 15db id say the gain is pretty well set.
Why not change the gain with the feedback resistors?
I am curious which inputs were used to test. I mean SE or balanced? I have seen the frequency response described in SIMULATIONS of the BH using SE inputs. I know, I know, its a weak comparison but the topology of the input stage and how feedback is applied are similar.