I'll give you another point of view if I may .....
It appears that with your Grados you are purposely reducing the mid range because you feel it's out of proportion. From my experience with the lower end Grados - they do have emphasis on both the upper mids and highs. I personally like an elevated mid-range, but I can understand what you're doing with your EQ.
That would suggest to me that you're taking a quite mid/high focussed headphone and trying to flatten it.
If that's the case, then I'd be recommending the DT880 over the DT990. The DT880 is a flatter presentation - has nice bass impact and extension (especially compared to your 225s). The mids are slightly recessed compared to the bass and upper end - but not excessively so.
Is there anywhere you can demo both the 880 and 990? It's worth doing. You'll find people on both sides of this particular fence. I really enjoyed the 990s bigger sound stage - but in the end the 880s over all balance was more appealing for me. It's something you really need to try to get a real appreciation. Both the 990 and 880 are very good cans for their asking price.