I think the most important consideration is the concentration of the water. If the you have permafrost making hard "soil" condition that would seem to indicate a fairly high concentration water- say, over 20% concentration. I think having fairly large area of concentration 20% or more which can be extractable [requiring relatively low heat [above the freezing point of water] in a vacuum] is minable. Water on the Moon is more valuable than gold on the Moon. On Earth you mine gold in solid rock miles under the ground at far lower concentration than less than 1%, on the Moon if you can only extract 1 ton of water per every 100 tons of "ore", you will be roughly 20 times more productive if instead you are getting 20 tons of water per 100 ton. You could have loose "soil" in bottom of shallow crater having only 1 percent concentration which less minable then extremely hard permafrost at the bottom of 5 mile deep crater which was 20% concentration.
If it requires 50 tons shipped to lunar surface to mine the 1% "loose soil" stuff to get 100 tonnes of water per year, compared to 50 tons plus additional 50 tons for dealing with harsher conditions of "permafrost in a very deep dark crater" shipped to lunar surface to mine 2000 tons of water per year- generally speaking, you pick the latter.