User blog comment:Salubri/Hollow. Arrancar, Espada & Vasto Lorde/@comment-1268838-20100818171824

The second Ulquiorra stated that Espadas 1-4 could not release under the dome, many of us immediately assumed that meant that those Espada were all Vasto Lordes. From the looks of things now, that assumption was correct - the separation in power at that point of separation was always just too great to ignore. Yammy is a weird case, so I'll leave that alone for now.

Grimmjow was Arrancar Doce, meaning that he was the second Numero to ever be turned into an Arrancar by Aizen. Depending on who the Espada were at that time, that would mean that Grimmjow has been around for quite a long time - because of that, I doubt that he reached the level of Vasto Lorde before becoming an Arrancar. Nnoitra has also been around for quite a while, so I am pretty sure he is an Adjuchas.