Hollogo however makes me wonder exactly how much more powerful high tier VLs are and if there is any true ceiling limit for them.
Regular hollow Vasto Lordes have a clear cut limit, that is why Aizen needs the orb; to break the limit of a hollow and a shinigami by merger. Ichigo's hollow on the other hand it's a Vizard with the hollow side having won over, not a transformation to a regular hollow, that is why there's no theoretical limit.
Of course, Ichigo's recent transformation is odd either way. He's attained a form greater that what all the other Vizard are capable of. When they became Vizards, it was through Aizen's prototype. Urahara using the real thing proved to be a failure.... it didn't work. It appears not even the orb could completely break the boundary of shinigami - hollow. The orb only seemed to initiate their battles against their inner hollow to the point that they could time them. Ichigo needed neither Aizen's prototype, nor the real thing. Like he is a true shinigami, he is also a vizard from birth.