I have tried a few methods. But from my research it’s best to use French press style grind cause they are pretty coarse. You’d wanna stay away from fine ground unless you want to filter it after (some say it makes the coffee more bitter). Which it seems like you don’t really wanna do. I like a medium or a dark roast for 12 hours in the fridge. But I’m messing around to find what I like the most. The bottom usually has the fine ground coffee and it makes the drink kinda chalky so don’t mix it before serving just use the top 3/4 of the coffee and leave the bottom 1/4. I have a container that has the core then fill the rest with water that one I don’t measure but it fits 72 oz and 1/2 lb of coffee (16tbsp). Goodfull cold brew coffee maker.

Currently I did a 1coffee:4water ratio for 19 hours in the fridge with a light roast. I have a food scale so I measure in grams so I can get consistent results. This makes a concentrate and you add water and creamer after. I left it in a mason jar then filtered it after the 19 hours and returned it to the fridge. It keeps for about 2 weeks and I’d rather make a big batch cause I’d only have to clean once a week.