Hi Rick,
I generally do description sheets and measurements on plants which are in full flower which I realise is slightly open to interpretation but by full flower I mean the segments have expanded to or at least are approaching their full dimensions.
For purposes of comparison and for doing descriptions I try and ensure that the specimen is fully established and of optimum development in size for its clone. But just to be confusing, their can be an enormous disparity between what a given cultivars can produce in measurement and markings from the minimum sized bulb capable of producing a flower, say a year three twin scale, and what results from a large full-sized healthy specimen.
This, in turn, leads to the frequently overlooked concept of clonal variation and the range of appearance in many characters such as markings and size, and even segment shape, that a single clone can produce which, in isolation, might give the false impression of the existence of more than a single clone being grown under the same name. I hope that makes sense!
