Hi David,
Here's the page on how to actually save a plant callout. You could put the "nr" right in there, but be aware that it would show up on area plant callouts as well.
Create New Plant Label Style:
https://www.landfx.com/index.php/docs/planting/customize-planting/labels/item/1193-new.html
I understand that the recommendations above are not great long term solutions. As mentioned, adding the capability to show quantity on a refnote callout is a high priority item on the wish list. Based on the current schedule of high priority improvements, it probably won't be available until 2017.
Thank you for pointing out some of the inconsistencies on that attribute page and the power tip video.
The old tags for plant callouts were ### and CODE. This was revamped for codes more friendly to stringing together attributes, and changed to QTY and GEN-SPE or GS. SIZE also changed to FIELD1 (because we made FIELD2, 3, etc available). They will all still work so that older user's old plans and preferences still work. We'll get to updating that page to reflect this, and I'll put the power tip video on the slate to be re-shot since it was shot during the transition between the two callout styles.
I hope that clears up your confusion.
-Amanda