Hi! Thanks for reading and for the compliments, I appreciate it.
For your purposes I’d probably pick the MDR-7506/V6. It’s not quite as isolating, but it’ll have a response that’s more in line with what you’ll find in working environments. It’s a better headphone for checking for flaws in audio tracks, and it’s a bit easier to EQ it against your monitors.
If money is no problem…I’d honestly recommend just buying both, seeing which one you like, and returning the one you don’t enjoy! They’re both good studio pairs. They’re both better suited to monitoring than they are mixing. And they’re both flatter than many other closed-back options.