I leave the dry feed available all the time, but I give them the wet feed as a treat, or in bad weather. Sometimes I feed wet feed twice a day (breakfast and dinner), sometimes once a day to lure them back into the coop at bedtime, sometimes on a whim because I want to watch them run toward me and gobble it up, somtimes I go for months without doing it, sometimes I do lots of small feedings in a day because I'm bored or because I'm teaching them to come when called.
In winter, when the water freezes, they get thirsty--and then they won't eat either. That's why I first started feeding wet feed (food + water, and they eat it fast before it freezes.)
In summer, if they don't drink enough in the heat, they also won't eat enough--and wet food fixes that too, because it's feed + water + they gobble it up.
For how much to make, I measure with either the serving container ("this full") or the feed scoop, based on how much they ate the last time. I don't want extra sitting around to go bad, and I know they can fill up on the dry food if I underfeed with the wet.