Mike, this was the reason for my reply. Naturally, I assumed you hadn't looked at the subframe & seen the factory adjustment is exactly that. No sarcasm.
No, the bolt in the hub is not eccentric, and it's actually bushed in the hub too. The back arm is a toe adjustment arm. For anything up to around 2" lowered the OEM eccentric will likely suffice.
Depending on how low you drop the car; the toe can end up being so far out that you cannot use the OEM eccentric bolt to adjust. This is normally at stupid "fitment' and "stance" brah ride heights.
For normal people; a more "eccentric" (more adjustment) eccentric will do. This is why they slot the hole in the subfame out a little more.
If that's not enough; you can move to the length adjustable arm; as per the dolts in that video who seem intent on using a power driver to undo every bolt, regardless of whether it saves any time, or is actually any easier.
With length adjustable arms; I have no idea why these guys feel the need to ALSO fit eccentric bolts; if it were me, I'd set the eccentric in the centre of its range, and finetune the arm length on a wheel aligner. Then you can make small + or - adjustments with the eccentric.
But hey; I don't use a power driver on pre loosened bolts either...