Hi Steve,
There is also some software on the market when using headphones in relation to 'the' actual sound on monitors. It may be not the ultimate solution, but you could try out Redline Monitor or Tonebooster Isone.
I quote: "...a stereo virtual reproduction system and listening room can now be experienced simply using high-quality headphones. The frequency response and the directivity pattern of the loudspeakers can be adjusted. Furthermore, the reverb time and volume of the virtual listening room and the distance to the virtual loudspeakers can be fully customized.."
It is independent of brand and type of your headphones in a way, so why not give it a try?
best,
Erik