If you want to brine split breasts, it won't take more than 4 hours. Use Kosher or canning, and consider adding spices to the brine and simmering to meld flavors. Chill brine before use.
What I do is I make the brine "strong", and add ice in a known amount to help chill faster. Or make it Friday and fridge it.
Consider onion, parsley, rosemary, paprika, thyme, celery spices- among any others you enjoy.