Ooh! good tip about grabbing the GC first (or early.) Though in most of my "finished" games, I don't care so much about how many mushrooms I get since food isn't as critical.
In my current "in progress" game, I working on getting Level 3 Medicine
before Level 3 Farming, so food is more critical. No GC yet, so I just grab all the kids I can until the "picking a mushroom" line doesn't appear.
BTW, on one of my computers, I changed the carring.png file to be twice as big as it normally is. All of the objects grew, but the main reason was to make the mushrooms easier to spot. Unfortunately, the mushrooms don't show up in Map Mode. I was hoping to "mushroom hunt" by making them easier to see when looking at the entire island area.

riality, in answer to your other question. It depends. If it is still very early in the game and you might not have enough berries, or berries and harvests on their own, you may want to pause the game overnight. Later, Harvesting the crops can substain a smallish (less than a dozen) population overnight at 1/2 speed. For larger populations, you really should have level 3 Farming until you get practice at finding the right balance.