Finally got my Make4 today. Was supposed to receive it in 2022, but the local post office and I both forgot about it lol
According to Final's tweet, the stock configuration is:
Nozzle front filter: D-6 (medium treble)
Nozzle inside filter: None (max treble)
Nozzle back filter: None (max treble)
Front vent filter: F-6 (close-to-max bass)
Back wheel: fully turned clockwise (max bass)
For now I've only experimented turning the back wheel, which adjusts the amount of air behind the driver. According to Final, this is what I'm supposed to hear:

... which is pretty accurate. At this stock config, the sound is clearly in the same vain as the E-series. I prefer this stock config (blue) over fully turning the back wheel counter-clockwise (red), which is still a nice warm sound, but doesn't quite have the epic-ness of the E-series.
Compared to stock Make4, E500 has less subbass, warmer midrange and similar treble. Compared to E4000, stock Make4 has similar bass, but a brighter midrange and treble. Here's a quick size comparison:
Since most of the customizations turn the bass and/or treble down, making the sound warmer and less V-shaped, I totally can see Make4 mimic the entire E-series w/ the right config. Someone in Japan have to have done it; I'll just have to find the right tutorial.
IMO Make4 should pretty much make E4000 and E5000 obsolete. That is, if you can find a way to buy the Make4. It is cheaper than E4000 and E5000, and neither has a real argument in terms of comfort against Make4. I can't wear Make4 to sleep, but neither can I wear E4000 and E5000. E500~E3000 should sell just fine, especially with E500 and E1000 using the same cable as Make4.