Played with an EQ for most of the day on equalizer APO trying to make the primes sound like my TH-X00s for electronic music. I think I got it roughly close, I'm getting a similar vibe from the two cans now but there is still some weirdness to tune out. I can get specific values if asked, but
this is what the eq settings look like. I'm surprised how high some of the values came out to be. Most of the tuning was done by direct comparisons with a blindfold on to focus on the sound, pressing the arrow keys to increase or decrease a selected frequency range I was listening for. Interestingly, the 2kHz - 4kHz range really affected the sound stage depth/intimacy but also heavily affected the visceral quality of the drums. Both of these qualities are some of the most notable differences between the stock sound of both headphones too. I looked into why, and it turns out that's the frequency range that is commonly attributed to the "attack" of instruments. I guess by increasing that aspect it also makes the affected instruments sound more intimate, thus pulling them and the overall perceived sound stage closer. Fascinating stuff.
Edit:
Tried smoothing out the response more, got rid of some of the weirdness.