Centering (Grade) of the stamp is always a difficult subject to approach. Namely, what may be very fine to one individual may be only fine+ to another. Also, the definition of a grade can vary greatly from seller to seller. Compounding the problem is that very fine for classics are usually different than that of modern issues.
As we primarily deal in modern issues, the following defines how we grade our stamps. Note that the following standard does not apply to classics. It would be too stringent to apply a grading standard used on modern issues to classics. Also on some classics where there is almost no distance between the design and the perforations, it is very difficult to find stamps where the perforations clear the design on all four sides. However, since classics will almost always have a scan that can be view before purchase, our grading standard can be easily judge.
Also, we do not use a grade above VF+. Applying grades of extra fine
and superb to modern stamps seems to be too marketing oriented as
most modern stamps will have very fine or better centering.
Thus, we will just use VF+ to indicate anything with above normal centering.