He is actually not using a phone with these. It is in fact one of the industry leading DAPs; iBasso DX300 with modified Amp12 card (to EXN). While it puts out a tremendous amount of wattage, for the Timeless, the amperages that it is capable of is the more important figure to drive ortho DDs, which is somewhere over 2 amps. And as mentioned, it is not the volume that is being defined by the ability to drive these, but actually properly exciting the driver itself. And for that all ortho dynamic drivers scale better with more amperage. Phones can drive them to be plenty loud, but they are not capable of putting out the kind of amperage that a desktop solution (or TOTL portable solution) can.
If you use a SPC or SPC hybrid, or pure copper cable, you would not need any EQ as those cables would help with any treble "piercing" issues.
I have went back and forth with many of my "end game" tips with these, and have finally (and actually) landed on the stock white (foam shaped) tips, for a compromise of comfort, seal, and overall sound. There are a few that sound a bit better, but don't seal as well, or some that get uncomfortable after a time. These seem to fit all three. Who'd a' thunk'?
I tole' ya' over on the DX300 thread that these were good!
Welcome to the club!
On the other hand, don't go selling off your IT07 just yet?! After you have had them a while, and then go back and forth, there IS a noticeable difference in the sound. Now, for me, that difference is the IT07 being better in almost every way. For you it might not be so, but I would advise waiting for just a bit before making up your mind about that (with all due repsect)...