The way "Craft To" works now means that the Prospector will stop working if there are that many or more clumps/stones in stock, that just doesn't go well with how the Prospector functions in my opinion. Imagine if the smelter stopped working because there were too many ores around or a chef stopped baking bread because he couldn't handle all those grains!
I would like to see a reworking of the Prospector's "Craft To" to mean "Craft until", so for example "Craft Raw Stone until 200" would mean that the Prospector stops working when 200 raw stones remain in stock and get back to work as soon as the amount of stone exceeds 200. This way the Prospector would work more in line with how I think most of us use it; to get rid of excess dirt and stone but without the need to babysit it if we want to keep some raw stone or dirt for later.
tl;dr: I would like the Prospector Shop's "Craft To" reworked into "Prospect until these many Clumps/Raw Stones remain".