I don't know about the 623C thing, that requires a lot of time and hoping your opponent is too stupid to punish it once they see the super flash.
Yeah, at this point I try to save meter for Veil Off almost all the time, but it's still not the greatest option.
Even moreso than the lack of invincibility on his moves, I feel like his pokes have strangely huge hurtboxes. Like for instance if Vatista does a slow orb off of her 2C, Gordeau can just do his slide (3C) or Hilda can do a 2C and totally beat the fireball, but pretty much all of Byakuya's long pokes (2C, 3C, 2B sometimes) will trade with it even though you're super far from it.
Or if Linne approaches with a 66C, none of Byakuya's normals can do anything about it except a super super super early 2C even though they are definitely long enough that it would make sense that they could work. It's like a lot of his pokes extend his hurtboxes before the hitbox of the move comes out...
Funny that Waldstein has no hurtboxes on his arms even though they're part of his body, and Byakuya has huge hitboxes on his blades even though they aren't, haha.