It may be naive of me to think this, but it seems like introducing a type of global variable for holding various common dimensions would be a super great feature for Vectorworks. Such a variable could be managed within the Organization dialog, similar to the way Levels work. For example, a variable "Panel Thickness" containing the dimension "3/4" might be used in any field within the the object info palette that accepts dimensions, such that panel thicknesses, reveal sizes, spacing, etc, might be changed universally in the project simply by updating the single variable.
I had the impression that Levels would partly serve this purpose, but It's been frustrating to discover that one cannot bind any arbitrary dimension to a given Level.