The scale is
Askin ~ Kisuke >= Aura > Tokinada ~ Byakuya ~ V2 Gerard
My line of reasoning for Tokinada ~ Byakuya is that it’s stated they have similar reiatsu levels and we know Shinigami battles are specifically determined by reiatsu. Additionally, Kisuke informs us it’s reiatsu that determines a Shinigami’s stats. Also, a fatigued Tokinada is able to take (albeit barely) Ginjo’s attacks. Ginjo being the guy who could possibly beat Hikone, Hikone being the child who scales above pretty much the entire EoS verse that’s alive.
Tokinada likely only scales to base Yoruichi and Byakuya. Not accounting for Shunko forms and Bankai. The reason being, Shunko Yoruihci was beating down Askin who you scale above Tokinada, and Byakuya scales above Gerard. Now you have Gerard at the bottom of the scale, but it's been stated that God Sized Gerard is the strongest Quincy after he had taken in enough Miracle damage, and this was pre Vollstandig and Pre Final From, both of which Byakuya went on to contend with. This is also consistent with Byakuya making easy work of an enemy that scales to Kyoraku in a 1 v 8. Aura and Kisuke are > Tokinada though, but so are Byakuya and Yoruichi at their full power.
There's a reason why Narita wrote Byakuya and Toshiro out of the story. They're still in the same league as Kenpachi, and unlike him, they would've have toyed around with Hikone like how Kenpachi would've, and the story would've been over at the beginning of volume 3 had either of them been there.
Also, I still wonder where people get the idea that the CFYOW versions of the characters are stronger than their TYBW versions? The only thing you can give them is the Soul Zenkai thing at best, but almost everyone would get that. Ginjo and the others weren't training for 6 months, its been stated that they were wandering the Rukon and in the Shiba house for that time. At best, they said their deaths helped them understand their Fullbrings better and what mistakes they made, but they weren't training. The Sternritters actually got weaker, as it's been stated they got nerfed after surviving the Holy Selection, yet they're still at the same level as the base Arrancar and the casual Fullbringers. The Gotei have been working on repairing the Seireitei and things of that nature. And at best, the only statement we get from Kenpachi is that he spars his squad's lower ranking officers to whip them in shape rather than him doing any hard training on his own. I read the official translations for all 3 novels and am wondering why there's this notion that everyone got stronger?
Ginjo might seem like the hardest one to justify since he scales to or above Hikone in Bankai at first glance, but this same Ginjo in Bankai was swapping hands with a full powered Fullbring Bankai Ichigo, while a weakened, injured version of this very same FB Bankai Ichigo was able to damage Base Yhwach who scales to or above Bankai Yama and is also High 6-A. Yhwach even wanted to go all out against this injured FB Bankai Ichigo and was excited to fight him. And before anyone says 'Ichigo easily beat Ginjo', although the fight was brief, Ginjo had the edge in Shikai to the point where he was able to deflect FB Shikai Ichigo's Getsuga with a casual slash. And in Bankai, they were both even and landing strikes on each other/damaging each other (we saw blood streaks implying injuries on both of them), until Ginjo got a mental/resolve nerf from Ichigo not doing what he expected and trying to understand him. We know how massive of an amp or nerf mental states and resolve is in Bleach, and it was even stated that Ichigo saved Ginjo in the end. From the point after his inner monologue, when he yelled Ichigo and fired the cero onwards was when his dropped. And we see it in both the anime and manga. They were even before that point.
The idea of the characters getting stronger between the FB/TYBW arcs and CFYOW isn't supported anywhere in the novels. The point about Kenpachi being the strongest pure shini could've been more valid of Toshiro and Byakuya, who were showed to be his equals or superiors in the TYBW arc, weren't purposefully written out of the story. Even narratively speaking, even though the Higher Ups in the Gotei made up a lie to keep the Tokinada-Hikone incident as small as possible, the rest of the Gotei, who aren't dumb by any means, found it a believable lie to send Byakuya and Toshiro on a mission where they thought Ichigo himself would need help with and actually be relavent to someone threatening to him.
And...this post ended up being longer than I meant to, sorry lmao