SMG1 - Ghostly invisible doors first key skip

Not sure if this is known. I haven't seen anyone use this method, and the closest I could find is one of Yoshifan's videos from 2010:
• SMGalaxy - Matter Spla...
Landing on top the first door doesn't seem that difficult. I start by running against the invisible wall. I then hold left on the analog stick while mashing C to make sure Luigi is facing exactly left.
During the backflip, I hold up-right for a bit (12 frames in this video), and then hold right until Luigi is above the door.
I hold down just before landing on the door--it seems to be easier to stay on top a door if Luigi is running rather than standing still. After running for a bit, I mash A to jump--I try to mash because sometimes Luigi's running animation is interrupted by a brief falling animation, and this can cancel my input.
The most difficult part for me is landing on top the last door, but this part is the same for every method I've seen. On this door, I run for a bit again and then hold Z while mashing A to long-jump.
Recorded on Dolphin. Input display by Yoshifan:
github.com/yos...