I think I've finally nailed it.
I have made my ES10 comparable to my W1000 in pretty much everything except for soundstage width.
And those who have listened to my modded W1000 knows it's no slouch.
The only downside is that the dampening mod would require a lot of precision, and also some fine-tuning (due to how precise it is), so I'm not sure how I can release it to the public now. And I get the feeling the stock ES10 ear cups would require a bit more tuning, since whatever I've done so far has been tuned specifically for the wood ear cups only.