What about just having a variable for DLC Yes/No like some other games have ( https://www.speedrun.com/Dishonored#Any%25 )? That way if anyone wants to filter the list to show only runs without DLC they can, but without adding a whole different category?
Hey, Ballistic has a tutorial on his Twitch page, it's 3 years old so a lot of the skips are outdated but the explanation for skywalking is still good:
It's a bit hard to explain but in general the inputs I do for skywalking is tap back (S) twice until you're stuck in the freefall position, tap right (D) once, then hold up left (WA) and turn the camera slowly to the left. Camera position is just as important as the keyboard inputs.
The Grim skip area is a good place to get a feel for how inputs/camera position influences skywalking movement.