Long overdue, finally putting this in a guide. This does not cover point routing to get CC for BCS, just BCS itself.

This method allows you to setup BCS (Black Comet Skip) in such a way where no analog stick movement is needed, even post-clip out. Simply wait a brief moment for the spindash to end, then use Chaos Control. This will net you more time to attempt CCG post BCS if performing CCGBCS in a run with CCG.

To get started, this is the general onlooking angle needed. It does not need be precise. Approximation is good enough.

Next is what I use for a frame of reference to setup. The geometry has signs of texture fill lines left on it. I marked the easy ones to spot, and circled in yellow a dark spot you will use for positioning.

Line up in front of this spot, slightly overlapping it, like this:

At this moment you should be able to see two more texture fill lines, and your shadow (not the character... your literal shadow) will be positioned to the right of the intersection of the two lines.

That image 4th is all you will need, the first three are just to help you find it the first time.

The target area is here:

Important: DO NOT touch the analog anymore once you are in position until you have used Chaos Control!!!

All that's left to do at this point is hold down spindash until it feels safe (experiment once you've got the skip down) and release.

Post BCS, if you are doing a NoCCG run, you will want to cancel CC and re-activate it just before it runs out to skip the spiral drop.

Don't fret about getting the exact position I'm showing. There is a great deal of variance that is safe so long as you are in the general area.

If you are still struggling to see the lines then use the dark spot (yellow circled) as your reference point instead. Below is a video of the above strategy in action for both NoCCG and CCG: