Help with modeling my ontology

Hello all,

At http://www.cropontology.org/ I'm trying to make things a little more RDF
friendly. For example, we have an ontology about Groundnut here:
http://www.cropontology.org/ontology/CO_337/Groundnut/ttl

I'm generating this from a somewhat flat list of names/concepts, so it's
still a work in progress. But I'm having issues making sense of it all so
that the ontology can be used by people that actually have Groundnut data.

For example, in that Turtle dump, search for "Canopy height". This is a
concept that people might use to describe the height of the canopy of their
groundnut plant, as the comment describes (this should be a Property not a
Class, but like I said, it's still work-in-progress). Let's try with some
sample data someone might have about groundnut, and see if I can further
explain my issue (I assume co: is a prefix for my cropontology.org site,
also the URIs are different but it's just an example):

    :groundnut1
      a co:Groundnut;
      co:canopyHeight xxx .

Ok here's the issue, we know that `canopyHeight` is measured using
different methodologies. For example it might be measured using a
methodology that we found to be described as "Measuring the distance from
the base to the tip of the main stem", but it might also be some other
method. And, funny enough, we also realized that it is measured using
centimeters, with a minimum of 0 and a maximum of 10cm.

So how should I make this easier on the people that are using my ontology?
Should it be:

    :groundnut1
      a co:Groundnut;
      co:canopyHeight "9.5cm" .

or should it be:

    :groundnut1
      a co:Groundnut;
      co:canopyHeight [
        co:method "Measuring the distance from the base to the tip of the
main stem";
        co:scale "9.5cm"
      ] .

Maybe I'm going about this the wrong way and should think more about how
this ontology is going to be used by people that have data about it... but
I'm not sure. Any advice would be great. And here's the actual browsable
list of concepts, in a tree sort of interface:
http://www.cropontology.org/terms/CO_337:0000039/

As you can see there's this kind of thing happening all over the ontology
where we have the Property->the method it was measured-> and finally the
scale. Any help? Thanks!