I have never wet-brined. A recipe calls for 4 fillets of salmon to a brine of 2 c water and 1 T salt. I want to do 2 fillets. So do I use the same amount of brine or 1 c water and 1.5 tsp salt??
As long as your brine covers the fish, the halving should be fine. A brine is more about the ratio of water to salt anyway, the amount of brine you make is more tailored to the amount of food you're making.