stocking meaning you keep them in boxes in a warehouse ready to be shipped asap, not mining with them

Shouldn't we just shipped them the moment they're ready ?
This is exactly what we're doing...
You could use a system that fulfills both criteria.
Build your miners, and put them up for sale the moment they are ready. Then ship them as soon as they are sold.
You seem to make such small batches anyway that you should have no trouble selling them.
Win-win.