It's easier to replace the lens in the closest IPD position (1), not the widest (3), as the lens apparently shouldn't go to the very end of the rail, i.e. they shouldn't touch the outer plastic in position 3, there's a small gap.

Also don't be surprised with double vision on the logo during the first boot, since the system boots with the last IPD it has seen (and you might've changed it when it was turned off). It should be gone shortly.

If you've removed the lens, when placing them back make sure they can snap in 3 positions, not 4. I initially hadn't notice mine snapped in 4 positions somehow (1, 1.75, 2.5, 3). I assembled the helmet, put it on and the lens immediately felt slightly misaligned. The software, of course, supports only 3 positions, it felt a bit dizzy, and I was able to see the edge of the screen. So had to disassemble all the way down again.

Apparently, the gear might have the wrong "phase", so you may have to manually rotate it to find the right initial position when replacing the lens. The easiest way, of course, is to pay attention to lens position in which you took them off, so you can replace them exactly the same way.

If you have trouble lifting the plastic fan assembly, check the ledge above the orange T2 screw. It might help to bend the plastic case a bit away from the screw (up) so the fan assembly has a bit more space and isn't held down by the ledge anymore.

When reassembling, pay attention to the bottom left part of the metal bracket. It has to go under the main board.

Another option for the midframe removal is to detach the cables from 2 more ZIFs (the smaller ones) below the "bottom cameras" ones pointed to by red arrows. It makes the total of 5 ZIFs for this step.

About the green part: do not pry under the foam and above the metal plate! There's a ZIF I accidentally broke this way (thinking it's a press connector with a cable that must be detached - no, it may be left in place). Unglue the metal plate under the cable, don't do anything with the connector.

If you're planning on removing the midframe later, the cables from two press connectors near the bottom cameras must be detached as well. One connector is visible on provided images in the bottom left corner. It's not in the guide yet, it seems, but the connectors must stay on the midframe (with the cameras) and the black upper cables are connected with components on the case. The connector itself is glued to the copper foil under it, so carefully pry from the bottom of the upper cable. If you pry from left or right, you can accidently unglue the connector.

If you're planning on removing the midframe later on, peel the black tape above yellow arrows off of the two cables it tapes together, because the left cable goes with the midframe and the right one must stay. The cables might twist when you remove the midframe and it'll get uncomfortable to peel it off in that position.

The two bottom screws here are P00 (and are slightly longer!), the two top ones are P000.

The "P0" (P000, actually) screws here are non-magnetic! Be careful not to lose them!